Problematic notion about Zone 5 & 6 story bits.

[Iscah]

See for me it just doesn't entirely work that Cahciua is the one to be in the position of the broader society. She has been in Alexandria for 30 years.
She's also a viera who's lifespan is ~400-500 years. and it has been only 3 years since Erenville left from Tural to Sharlyan. So that means Erenvilles mom and mentor must have been really old already before she got swooped into the dome.

Viera lifespan is more like 200 years, but in any case since we're not told how she died, we don't know if she actually did live that long overall. That said, we can assume she was at least around 100 since she travelled with Gulool Ja Ja eighty years ago.

I don't think that inherently undermines her ability to have an informed opinion on the Alexandrian mindset, though. Thirty years is almost half a human lifetime. It's a long time to describe as "only".

[Alenore]

Viera lifespan is more like 200 years

Much more than that. Almet says to Urianger that Viis can easily live to see "3 of your elven lifetimes". Elezen live ~120 years, so that'd bring Vieras to a minimum of 360-400.