I just dont understand whats going on with the 24 man storyline

[Nuach]

The Echo flashback you see has Orran Durai explaining to Delita that Ajora betrayed Hydaelyn by summoning Ultima. And since he refers to Ajora as "first of the Zodiac Braves," that implies this was a really ancient event.

Apologies but I disagree with you here, though my thoughts rely off of some FFT info, I believe that Ajora lived during the late 3rd Astral Era or the 4th Umbral Era, with Ramza and the events of FFXIV's version of Tactics happening during the mid to late 4th Astral Era.

One of the major pieces of of evidence that I have for this is that Ajora is noted during FFT to have lived during a time when ships flew across the sky, and an oppressive empire ruled where Ajora lived, this sounds rather like the Allagan Empire to me, with the 4th Umbral Calamity bringing the end to it (I know that it was the Holy Ydoran Empire in FFT, but hey if it fits). Or possibly during the 4th Umbral Era with remnants of Allagan airship technology remaining in usage for a time until the destruction of Mullonde (by Ajora summoning Ultima) along with said airship technology. I'm not entirely convinced that Ajora was a WoL, but I could see it, so I won't contest it. The 4th Astral Era is mentioned in the EE as a time of great religiousness which used the Allagan Empire as example of the sin of hubris, this very much seems like it fits together with the Church of Glabados and it's teachings, which leads me to believe that Ramza's actions took place during this Era.

Another thing that points towards this timeline is that it wasn't until the actions of Coinach that the Allag's existence was confirmed in the 6th Astral Era, whereas the Zodiac Braves as a reoccurring group are common knowledge culture heroes in the near east of Thavnair, and presumably Dalmasca, pointing towards these events happening after the fall of Allag. The timeline of Ramza's actions happening during the 4th Astral Era also gives plenty of time for the Garleans to be descended from the Gougans, with all the requisite migrations, and still allow them to be a remembered distant golden era by the annals of Garlean history without having them be pre-Allag (because then there would be no reason to remember the mere Gougans when the Allagan reached higher in it's hubris).

This also lines up with the idea of Ajora as the "first of the Zodiac Braves", there would be three major distinct generations of Zodiac Braves that we know of. The first with Ajora, a group that used the auracites during the late 3rd Astral Era, and thus derived the groups name from them, followed by Ramza and his group, some thousand or so years later during the 4th Astral Era, and then during the waning days of the 5th Astral Era the Zodiac Braves that are referenced during the ARR Relic quest, since for that one there is specific references to Nym, the War of the Magi, and the 6th Umbral Calamity. I could very well see some minor generations of Zodiac Braves dotted here and there that claim the name of Zodiac Braves as well, but those 3 are the ones we know of.

As for the timeline of the naming of Ultima, I am of the thought that Ultima was originally nameless, and extremely destructive. Then during the Allagan Empire, Allag learns of the name and destructive potential of the spell Ultima from Omega (as Cid implies), presumably Omega had encountered it during the voyage between Stars, which the Allagans then conflate with the nameless horror that they are presumably aware of from an earlier era (or perhaps Ajora names Ultima himself), and thus we get Ultima, the High Seraph. I am not convinced that Ultima had anything to do with the creation of the Heart of Sabik, it could easily have been a relic from an earlier Astral Era (The Second Astral Era, maybe?), or perhaps the Heart of Sabik is not of the very Star of Hydaelen, perhaps it is something that predates the very world.

Hopefully this wall of text is informative, and elucidates my thoughts on FFT's timing in FFXIV.

[JeanneOrnitier]

Correct me if I'm wrong but I believe the Holy Ydoran Empire is mentioned as the empire Ajora summoned/unsealed Ultima against in XIV, not Allag.

[Remedi]

Both Crystal Tower and the Shadow of Mhach raids have those elements but I would absolutely say Mhach is the better contender for something unique to just XIV.

Void Ark ties directly to the events of the War of the Magi, being the Ark Mhachi used to escape the great flood (which lead the Lost City of Ampador into it's mold ridden state). The ark is completely abandoned and ravaged by voidsent as the original Mhachi sacrified themselves to seal the voidsent (powering the ship) to prevent them from escaping.

The Wheeping City of Mhach is the the city of the mages of Mhach which again ties into the Ampador and the Void Ark.

and Dun Scaith is the final conclusion which was built by the Mhach as the final haven to live after avoiding the flood, which in turn was taken over by Diabolos (who has been a present threat since Ampador and Void Ark)

All of those elements feature recurring threats from the Final Fantasy series but is tailor made using XIV's story as the main base. It's not just an almost complete retread (as Crystal Tower raids were in terms of bosses) compared to the original.

Crystal tower has nothing original of XIV, they just took most of the plot points of III and just slapped an allagan empire on them, Dun scaith is actually original even though most of the players have some inspirations from some folklores, but afaik they never were any past FF plot points.
Realistically though Tactics is a much better integration of another FF lore into XIV simply because they really went out of their way to meld it to make it fit (well we only have CT as a comparison and the bar wasn't set that high but still).

[Cilia]

The Crystal Tower is very similar, but it does have some significant differences to its appearance and story in III. So, here's a Cliff's Notes version...

In III, it's just kind of there as Xande's stronghold. In III, Xande was one of the Archmagus Noah's apprentices along with Doga and Unei. When he reached the end of his life, Noah gifted his apprentices each with their own special power: Doga was given power over magic, Unei was given power over dreams, and Xande was given mortality.

Naturally, Xande wasn't very happy about that, and began scheming a way to grant himself immortality. To this end he flooded the world in a dark ocean, stopping time everywhere but on a floating continent, and holed himself up in the Crystal (Syrcus) Tower. He remains there until confronted by the party, attacking them through proxies in an attempt to stop the Warriors of Light from gaining power from the Crystals necessary to defeat him. Xande has no pact with the Cloud of Darkness in III, but his actions inadvertently end up summoning it after his death at the hands of the Warriors of Light.

That's significantly different to XIV's incarnation - notably III Xande has the exact opposite goal of XIV Xande. All the bosses are taken from III monsters, and there are a ton of references, but the Crystal Tower series isn't a carbon copy of III.

Shadow of Mhach is mostly original. Mostly. Some of the bosses are references (Cu Chulainn, Echidna, Ozma, Calofisteri, Diabolos) and the War of the Magi is used as a backdrop, but it expands the lore of XIV greatly without relying too much on previous titles and delves much further into the Celtic Ulster cycle mythos in so doing.

Return to Ivalice... is a lot like III in the sense that it takes elements from previous title(s) and rearranges them to fit XIV's world, but it feels like locations from Ivalice titles were just grafted on rather than adapted (or Hydaelyn was adapted to fit the Ivalice elements, when it should be the other way around). Leaving aside my personal distaste for Ivalice, that's my biggest gripe with it.

[Fenral]

Wiping City, er, Weeping City also uses a heavily altered version of IX's regular battle theme for background music (well, a mashup of IX's battle theme and XIV 2.0's Mor Dhona theme), as a reference to Ozma's origins as a random encounter superboss in IX.

[Remedi]

I'm afraid I disagree, the whole CT arc isn't just very similar, it's essentially the final 3 dungeons of FFIII ported to XIV, slapped some allagans shenanigans on it and called it a day. It's down to the very entrance to the tower.
Ivalice on the other hand can be actually considered a remaking of the whole ivalice alliance since it reworks most of the historical events to create what can be considered a new continuity to that setting only tied to the XIV setting and frankly it is miles better adapted than the CT storyline. Luckily we are getting new material to CT to actually rectifying those mistakes which were made simply because the game was new

[Cilia]

Wiping City, er, Weeping City also uses a heavily altered version of IX's regular battle theme for background music (well, a mashup of IX's battle theme and XIV 2.0's Mor Dhona theme), as a reference to Ozma's origins as a random encounter superboss in IX.

Ozma wasn't a random encounter! You had to go far, far out of your way to fight him and are given a warning before the fight! It's not like I's Warmechs!

I'm afraid I disagree, the whole CT arc isn't just very similar, it's essentially the final 3 dungeons of FFIII ported to XIV, slapped some allagans shenanigans on it and called it a day. It's down to the very entrance to the tower.
Ivalice on the other hand can be actually considered a remaking of the whole ivalice alliance since it reworks most of the historical events to create what can be considered a new continuity to that setting only tied to the XIV setting and frankly it is miles better adapted than the CT storyline. Luckily we are getting new material to CT to actually rectifying those mistakes which were made simply because the game was new

If you look only at the locations sure. Yeah, they put the final dungeon(s) from III in the game... but despite sharing locations and character names the story is a bit different. (Did you know that in III Amon isn't a brilliant aetherochemist responsible for cloning / reviving Xande from the dead? He's just a palette swap of Hein, the final opponent faced at the end of the game's Floating Continent arc who used dark magic to animate the Elder Tree and use it as a mobile fortress, christening it "Castle Hein." Hein's gimmick was switching his elemental weakness; Amon is just a random encounter in the Crystal Tower.)

Using broad strokes like that there's nothing original in Return to Ivalice... they swapped Tactics and XII's places in Ivalice's timelines, replaced the Archadian Empire with Garlemald, and gave us some companions to deliver infodumps before and after the raids. (New monster designs though! Some of them, anyway.)

They made some adaptations (such as making B'gamnan a Dalmascan fusilier instead of a sky pirate, giving the Garleans ancestral ties to Goug, and apparently giving Delita more overt nobility), but leaving out locations and monsters the story feels a bit more cut and paste to me than the Crystal Tower's did. (Might just be my distaste for Ivalice talking though.)

[Nuach]

Correct me if I'm wrong but I believe the Holy Ydoran Empire is mentioned as the empire Ajora summoned/unsealed Ultima against in XIV, not Allag.

I don't remember the Holy Ydoran Empire being name dropped in the dialogue, but I don't doubt you, I probably missed it or forgot it. That just pushes me towards my thought that Ajora's life was during the 4th Umbral Era rather than Ajora's life being in the 3rd Astral Era, with the Holy Ydoran Empire as a state in the post-Allag period, at least still capable of airship technology until the destruction of Mullonde, but late enough that the religious influence (though Pharist at the time rather than the Church of Glabados) that would dominate the 4th Astral Era to be present.

Consequently this also makes me think it even more unlikely for Ajora to be a WoL, instead Ramza's statement of Ajora betraying Hydaelyn as less a personal betrayal, and instead a more "enemy of the world" phrasing.

[Rocl]

I don't remember the Holy Ydoran Empire being name dropped in the dialogue, but I don't doubt you, I probably missed it or forgot it.

I don't think it's mentioned outside of the small talks you get with the two requisite lore-dump NPCs aboard the Prima Vista (the Dramaturge and Jenomis).

[Remedi]

If you look only at the locations sure. Yeah, they put the final dungeon(s) from III in the game... but despite sharing locations and character names the story is a bit different. (Did you know that in III Amon isn't a brilliant aetherochemist responsible for cloning / reviving Xande from the dead? He's just a palette swap of Hein, the final opponent faced at the end of the game's Floating Continent arc who used dark magic to animate the Elder Tree and use it as a mobile fortress, christening it "Castle Hein." Hein's gimmick was switching his elemental weakness; Amon is just a random encounter in the Crystal Tower.)

Using broad strokes like that there's nothing original in Return to Ivalice... they swapped Tactics and XII's places in Ivalice's timelines, replaced the Archadian Empire with Garlemald, and gave us some companions to deliver infodumps before and after the raids. (New monster designs though! Some of them, anyway.)

They made some adaptations (such as making B'gamnan a Dalmascan fusilier instead of a sky pirate, giving the Garleans ancestral ties to Goug, and apparently giving Delita more overt nobility), but leaving out locations and monsters the story feels a bit more cut and paste to me than the Crystal Tower's did. (Might just be my distaste for Ivalice talking though.)

I played III, I know about the story and enemies, I know that Amon was an eureka boss guardian to one of the sealed weapons and palette swap of Hien, just like I know that Syrcus tower had only 1 boss which was Xande but they simply took the bosses of Eureka and placed them there so inpractice they changed nothing,
You can't really say that they really went out of their way to place the III version into XIV since as I repeat they choose some characters and slapped some allagans shenanigans on them it's not a reimagining of it and I do think that you smply dislike the setting as you said and realistically this game has been a cut and paste of many FF moments that saying XII crossed the lines is wrong.