Inconsistencies with the sundering (Spoilers)

[Kazhar]

Also why the heck weren't Elidibus, Lahabrea, and Emet Selch sundered? Is that explained in the game later at all?

It wasn't explained in game, but in a Live Letter. (Part LXVIII)

Q: I’d be interested to know how the unsundered Ascians (Lahabrea, Elidibus, and Emet-Selch) avoided being kicked into fourteen pieces by Hydaelyn.

A: As Emet-Selch implied towards the end of the 6.0 main scenario (“So, here I am Venat. I suppose you needed me to tie it all together…”), Venat had purposefully allowed him to survive. The attack intentionally left something like an opening which Emet-Selch could just barely wriggle through. With that said, with the limit of Hydaelyn’s full power behind the attack, fine-tuning wasn’t possible and whether or not he would actually survive was somewhat of a gamble. In the end, Emet-Selch, with the help of Lahabrea (who happened to be nearby) and Elidibus (who had fallen from Zodiark’s core), was able to evade the attack by temporarily escaping to a rift between dimensions.