1.) The Circle of Knowing knows of the Echo but they do not possess the power. They're in the Circle of Knowing because they're said to be reincarnations of the Twelve, the Archons. Minfilia tells us that 10 years ago the Echo began to appear in mass, same time as the Battle of Silvertear Skies. The Echo could have came from the Primals being released, it could be a power that was brought out when the aether was disturbed, it could be the call of the Mother Crystal ("Heed the Crystals Call," could literally be a hint they give us).
2.) First time I've heard of Minfilia surviving an imperial attack in Mor Dhona. If you've read what I posted you will know how everything lines up. Ascilia comes to Ul'dah with her father Warburton shortly after Ala Mhigo falls. We arrive in Ul'dah and step off the chocobo carriage and see the Event (the starshower) during this, everything around us changes. Somehow Grinfarr and the Lala Twins are on the same caravan, Ascilia and her father appear, and Thancred walks away with 2 women. Also Ul'dah is currently celebrating and having a festival. During our ride in, none of this was going on. People were bartering in the stalls and there wasn't so much of a commotion. Simple to say we are in an Echo and everything we experience at the time is an Echo. The whoosh noises we hear during these quests are Echo jumps, we are Echo jumping inside an Echo. At the conclusion of the quests we see a more in-depth starshower and noises ring in our head and we pass out.
Now prior to the crypt scene, spoilers aside, we bump into Minfilia and she says things along the line of she's surprised to see us here. Clearly meaning she's met us before, but we have not met her? There's a reason why their names are similar, same reason Ul'dah and Sil'dih are similar. This is how the world operates. Not only does a name change take place, but in each story there's a name change. Krimm, Ascilia, Sthalman (think that's it, typing this hastily and too lazy to look for the real spelling).
As for the last starshower I can't tell you what it is, but I believe it's a vague premonition for the 7th Verse of Mezaya Thousand Eye's The Divine Chronicles. In Tanaka's story and in Yoshi's story this vague disaster could mean anything and in Yoshi's story it's Dalamud and Bahamut.It's the heaven's spewing crimson flame and it has everything to do with our Echo, as does the first starshower.Ne'er till land consumes sun can sea bear moons.
Heavens spew crimson flame, hells seep black dooms.
Stray seeds quicken in ash's grey embrace.
Valiant blades forged under the Twelve's good grace.
When I came up with the theory of Ascilia == Minfilia, I worked very hard on it. I watched every Cutscene hundreds of times and read every line of npc dialogue even more times, looking for those subtle meanings. The conclusion I came up with was that, Ascilia grows up to be Minfilia. Catapult was able to come up with the same conclusion of Krimm growing up and being the Hermit.