Serendipity granted me the day off, so I powered through all of it.
Ugh.
MSQ
Not as relevatory as expected. Other than Elidibus stepping onto the stage using Ardbert's body as a vessel (as predicted) and the existence of one Venat who served as the leader of Hydaelyn's summoners (again, big surprise), there wasn't a whole lot of new information.
According to Elidibus anyone is capable of using the Echo, it just takes a starshower calling back to the Final Days to trigger its awakening. While this is a plausible scenario, I find it difficult to believe in truth as such events have occurred before without everyone waking to it. (See: 1.0 coming of the Warriors of Light.) It's also revealed that the Convocation defector, implicitly the Warrior of Light's Ancient self, did not join the faction that summoned Hydaelyn - as far as we are aware, at any rate.
Zenos is not actually on the First, and the scene of him in Amaurot is just a dream of his. His mysterious new friend appears to have secondhand knowledge of the event, and nothing more is really explained yet.
Sorrow of Werlyt (Cinder Drift / Ruby Weapon)
Phase 1: Not so bad, it's got some tricky techs but nothing I can't handle with a little practice. Goin' down pretty fast, I bet it's got some secondary form / phase or whatever...
Phase 2: WHAT THE KUPO IS THIS EVANGELION SHIT?!
Ehem. So the new Weapons are all like that reverse-engineered Ultima copycat, augmented with the combat data of other great warriors to help their pilots... but either kill said pilot as a consequence, or pushing the machine too far results in the personality data overriding the pilot and freaky shit happening. Whacko mad scientists, those Imperials. Hojo would be proud!
Run by a rebuilt VIIth Legion, though the acting Legatus remains unclear, and the Weapons themselves are apparently all going to be piloted by a group of Auri orphans Gaius took in a la Livia. The pilots' hair colors seem to be indicative of their respective Weapons, so we've likely got Sapphire, Emerald, and Diamond to look forward to in that order, with the last being co-piloted by the two white-haired Au Ra Pacific Rim style.
And, Gaius' thus-far silent right-hand Duskwight seems to be the one holding his reins and has sworn to kill him if he so much as thinks of going back to the Empire. Couldn't be simple, could it?
Eden's Verse
Heritor Ramuh: Ramuh mixed with Ixion. Instant death mechanics everywhere!
Heritor Garuda / Ifrit: Not so bad, then they fuse Dragon Ball Z style! Still a pretty easy fight...
Idol of the Dark: Not hard per sé, but definitely very tricky.
Heritor Shiva: Easily the most interesting boss of the lot - a mashup of Shiva, as channeled by Ryne, with influence from imagery of Hydaelyn Herself as we saw it in Shadowbringers! Easily the coolest (pun not intended) and by my measure fairest boss of the lot!
All elements restored, Thancred and Urianger leaving the project. As Thancred puts it Gaia is "prickly" to say the least, but appears to be getting better after helping Ryne after she lost control of Shiva. There are still a lot of questions surrounding Gaia, but there should be some answers to those in the last Eden chapter.
The "faerie" mentioned by Gaia is yet another shout-out to VIII - in that game during the times Squall & co. were aiding Laguna through Ellone's magic, he attributed the extra combat power to "faeries." Gaia's seems to have more sinister ulterior motives though.