The Reasoning behind The Sundering? (*6.0 Endwalker Spoilers*)

[Erendis]

Actually, we heard from... rather a few of them. And by my count, the ones that didn't want to come back, or at least seemed to make peace with the fact that wasn't happening...

• Emet-Selch
• Mitron
• Loghrif (sort of, that one's complicated)
• Elidibus
• Fandaniel (in all identities)
• Hythlodaeus
• Most unnamed Zodiark sacrifices
• Venat

This whole list is such a huge stretch that it does not hold any water. There is Hades, who directly said it. And there is loony Hermes who already wanted to kill everyone while everything was still unsundered. I would count him as 0.5 at best since he did not care about Etheirys at any state. Mitron and Loghrif hope to meet again in the future, maybe. Loghrif actually chose to live here and now with sundered people (1/14, not even 8/14) even after her memories were restored by Mitron. Hythlodeus would most definitely stay if Hades did since he only wants to be by his friends' side. Venat did not say whether she would like to stay or not, we just know she is gone completely and has not even a choice anymore. Elidibus chose to sacrifice all of his aether to save sundered planet without any hope to have it whole again. If that means he is completely gone without any choice like Venat, I am not completely sure. As for sacrifices, they wanted to protect the star. Now that they do not need to do it any more who knows what they would want...

[Absimiliard]

As far as we know, 100% usage of spiritual aether means soul destruction. At this point there's a reasonably large list of NPCs that won't be coming back, Elidibus and Venat among them.

[Cleretic]

This whole list is such a huge stretch that it does not hold any water. There is Hades, who directly said it. And there is loony Hermes who already wanted to kill everyone while everything was still unsundered. I would count him as 0.5 at best since he did not care about Etheirys at any state. Mitron and Loghrif hope to meet again in the future, maybe. Loghrif actually chose to live here and now with sundered people (1/14, not even 8/14) even after her memories were restored by Mitron. Hythlodeus would most definitely stay if Hades did since he only wants to be by his friends' side. Venat did not say whether she would like to stay or not, we just know she is gone completely and has not even a choice anymore. Elidibus chose to sacrifice all of his aether to save sundered planet without any hope to have it whole again. If that means he is completely gone without any choice like Venat, I am not completely sure. As for sacrifices, they wanted to protect the star. Now that they do not need to do it any more who knows what they would want...

I'm not entirely sure you understand the purpose of the list. These are the Ancients that, overall, seemed to die content with that fact, to contrast with the much shorter list of the ones that weren't.

Emet-Selch directly said it, yes.
Mitron wasn't exactly happy with the fact, but accepted it.
Loghrif is weird because we kinda have to synthesize her stance from Gaia, but that final scene with Mitron does effectively say that Loghrif is happy with yielding to Gaia, and maybe they'll meet again in a spiritual sense. If Loghrif counts anywhere she counts here, but if you wanted to remove her I wouldn't argue.
Elidibus had some trouble, but overall embraced... whatever cessation of self is in store for him, be it reincarnation or not.
Fandaniel was suicidal. That's not a great way to embrace your inevitable end, but it unarguably is doing so.
Most of the unnamed sacrifices we hear from in Mare Lamentorum seem okay with their fate... except for the part where it's not working. There are some that clearly regret their choice, but it's not overall; mostly they're just anxious about other things.
Hythlodaeus seems like he could go either way; if he got to live again he'd be cool with that, but he's also entirely okay with going forth into death. Which frankly concerns me; I feel like you should have a stronger stance on that, dude, that is a weird fence to sit on.
And Venat states directly that she's happy with her fate. That fate may not be reincarnation, but she's happy with it.

[Absimiliard]

Hythlodaeus seems like he could go either way; if he got to live again he'd be cool with that, but he's also entirely okay with going forth into death. Which frankly concerns me; I feel like you should have a stronger stance on that, dude, that is a weird fence to sit on.

I got the impression Hythlodaeus was more interested in seeing how the final chapter in the story of his people would play out than actually coming back to life. Being given a momentary (but very important) role in the salvation of Etheirys was just a nice bonus.

[Theodric]

In Hythlodaeus' case we're talking about a character who was selfless enough to sacrifice himself to Zodiark in order to help restore Etheirys after the Final Days struck. By his own admission, he wasn't a 'fighter' in the same way as Venat or Emet. He also states in Elpis that he sees the willing return to Etheirys as a beautiful moment.

[LystAP]

I got the impression Hythlodaeus was more interested in seeing how the final chapter in the story of his people would play out than actually coming back to life. Being given a momentary (but very important) role in the salvation of Etheirys was just a nice bonus.

My general sense is that he and Emet are waiting for the WoL to pass on, so they can be reborn together to have new adventures.

[Theodric]

My general sense is that he and Emet are waiting for the WoL to pass on, so they can be reborn together to have new adventures.

A rather excellent premise for FFXIV-2!

[Rannie]

My general sense is that he and Emet are waiting for the WoL to pass on, so they can be reborn together to have new adventures.

My impression as well even if Emet played grump when it was suggested