The second is my theory as well. Since you mentioned Etro, and I'm always mentioning XI, I'd like to point out that's also what Altana did. In her compassion and love, she basically caused a breakdown of existence and everything started devouring itself (Atomos).

I've seen it mentioned, too, in a similar vein that they might go full FFIX, with Zodiark and Hydaelyn being the Terra/Gaia and the Ascians working as the "angels."

Honestly, we can make up theories forever but none of them will probably be answered until 4.X or 5.0. It's going to eat me alive.

(The only theory I'm close to certain about, however, is that Pashtarot will be the next Ascian we kill due to being the last remaining of the watery triad, which seems to be the "problematic" of the Ascian bunch).