As for the rest of it

Not much else besides what’s already out there, no. The most recent article about it said that it might be a Japan exclusive and as far as I know it’s not up for pre-order so that adds some credence to that.

There’s lots of rumor and hearsay and nobody really knows concretely till Square Enix announces something.

If Disney (or Squeenix, if FF13-2′s Snow cop-out is any indication) could commit to that, it’d make for a neat “Light =\ Good” plotline and it’d make for an even better Eraqus parallel for her*. If they do; awesome, when they don’t; fanfic. Or fanart, whatever floats your boat. That said, she’d make for a beautiful bossfight for Riku’s section before coming to her senses in time to knock the senses out of a few Xehanorts.

Overall though I think they might be keeping it too cut and dry but everything’s so vaguely defined I’m just along for the ride at this point.

In Back Cover it’s revealed that Gula did in fact intend to summon Kingdom Hearts. Now, I’m positive that war would’ve eventually broken out (you don’t get to have your Union leaders openly duke it out in the street & not have tension + that damn Book of Prophecy said so) but it might’ve taken longer had this not been the conclusion Gula came to. This is largely because he needed more lux which lead to fighting over it which lead to inter-Union member tensions being exacerbated. 

We even see this in KHUX’s cutscenes at least once where wielders are arguing over Heartless and lux but I can’t recall if it’s before or after the missions where you see Invi and Aced fighting. Either way they were already bickering among themselves about lux in general but once higher quotas were put on the members it all just kinda snowballed.

Even better there’s scenes between Player, Skuld, and/or Ephemer that usually have a line somewhere to the general effect of not worrying/caring about them being in a different Union. Cross Union friendships were apparently rare already, there’s a lot of loyalty involved and anyone who steps outside of that would likely have issues with being perceived as disloyal. Like a Gryffindor being friends with a Slytherin except all the time and there’s magic key-swords instead of wands.

I think she’s got a pull chance for that Top Drawers Deal thing they’ve got now? 

From the website “1 turn: ↑ Reversed STR by 2, STR by 7, PSM-STR by 6, ↓ targets’ DEF by 3 & PSM-DEF by 4. Enemy countdown +1. HP recovery LV 4. Fills 5 gauges.“

The thing there is that it (at least now with what very very little we know) seems like the Master of Masters intentionally set them up to fail. He gave them all books (most likely) knowing that it’d become a self-fulfilling prophecy.

Then he proceeded to goad Aced into wanting to usurp Ira, definitely understood that Ira isn’t quite the most inspiring leader figure and would eventually fall short of Aced’s expectations, and sets Gula up to look suspicious to and be suspicious of everyone else.

Invi, he basically ties her hands by assigning someone who’s in the thick of things be a mediator/observer knowing that she’d probably do something that’d push everyone but Ira away. Ava is the only one he didn’t screw over in some way but her secondary role was entirely based around the War definitely happening and his students definitely falling into the trap laid out for them.

Except maybe Luxu but he hasn’t shown up yet so we’ll see.