The questions I want EW to answer the most: WHY and HOW was the world sundered?

[Vyrerus]

So in this case, the English script having a possible subtle reading that both Zodiark and Hydaelyn supporters are minorities in greater Amaurotian society... it needs more evidence than 'curious word choice'.

I get what you mean with the first bit here. I've been opposed quite readily for picking up on English word choice in other scenes, where JP FR or DE script turn what I thought was an amazing read into a nothing-burger(though apparently sometimes this makes people realize other cool things from the surrounding context).

I don't get this sentence though. Are you saying you can't nail down your assertion? I mean, that's how it reads since I'm going with the angle of what's presented in the game(and doubt the other language scripts can do much to reverse that). I've said that Zodiark supporters are the majority of Amaurotine society. You said we can't be sure of that, even though it's given to us in triplicate in game. Once by Hythlodaeus, once by Emet-selch, and once by Venat's holo record. We could say Hythlodaeus and Emet-selch are the same source, so of course they agree. Despite that bias, Venat, the dissenter's side, also agrees. So what's the hang up?

[Cleretic]

I don't get this sentence though. Are you saying you can't nail down your assertion? I mean, that's how it reads since I'm going with the angle of what's presented in the game(and doubt the other language scripts can do much to reverse that). I've said that Zodiark supporters are the majority of Amaurotine society. You said we can't be sure of that, even though it's given to use in triplicate in game. Once by Hythlodaeus, once by Emet-selch, and once by Venat's holo record. We could say Hythlodaeus and Emet-selch are the same source, so of course they agree. Despite that bias, Venat, the dissenter's side, also agrees. So what's the hang up?

What I mean is that the actual wording of that line in English ("You know as well as I that but few support our cause. Far fewer than they who place their faith in Zodiark.") could be read as meaning that Zodiark support also isn't all that big, but the core intention is clearly that Venat's crew is going up against a relative giant, and any indication of the Zodiark support's comparative size is incidental. If every single script confirmably said much the same thing, then it could have weight, but there's easy ways to write that in ways that don't suggest Zodiark support is also small ("Those that support our cause are dwarfed by those that support Zodiark", for example).

Basically: as interesting as I find that reading of that line, by itself it's extremely weak evidence I can't stand behind.

By the way, you do keep mentioning the sacrifices as if it's confirmable indication that Zodiark support is in the majority, but there's two things to take into account there:
1. We don't actually know how willing those sacrifices were. The initial sacrifices were probably ultimately voluntary, albeit under duress ("we're all gonna die anyway, no reason not to"), but all our knowledge of the second sacrifice's existence comes from a single Hythlodaeus text box that at the very least confirms it wasn't in red-alert contexts. Again, we don't necessarily know that Amaurot was democratic, it'd be a fair belief that they didn't necessarily go purely voluntary on that one.
2. Even if it was purely voluntary (in fact, especially if it was)... remember that at that point, they were down to roughly 25% of the population, and that 25% were the people who refused/dodged calls to sacrifice to Zodiark twice. Chances are most of Zodiark's actual opposition is still standing, while most of Zodiark's true believers have by now jumped in the grinder.

We're probably never going to get actual numbers for either, but I do think it's folly to assume that, especially by the end, Hydaelyn support was a small cell of extremists.

[Veloran]

It's my belief that the Venat faction summoned Hydaelyn for the purpose of sundering the star explicitly, and that this was done in order remove the Ancient's creation magics from the picture because that is what caused the Final Days, somehow. Specifically I think that in the same way conscious thoughts could alter concepts and produce strange creatures, subconscious thoughts could also effect the process and create some kind of hidden byproduct, which eventually metastasized within the Lifestream as the Sound. And while Zodiark could alter the laws of reality to undo the threat, he couldn't change human nature to prevent it from arising again in the future. Thus Hydaelyn sundered the world and it's souls, preventing living things from using creation magic (hence why in the earliest eras nobody could use magic at all), and in so doing preventing the Sound from reappearing.

This new Final Days appears to be happening as a result of countless Primal summonings (bootleg creation magic) instigated by mass torture, so that would explain how it's being fast-tracked so readily.