For those not in the know, the Convocation of Fourteen are all named after the Scions of Light mentioned in the Espers' bios from XII with three exceptions: neither Zodiark nor Ultima have counterparts, so Zodiark's representative in this game is Elidibus (in Tactics a sorcerer who held the Ophiuchus stone, letting him summon Zodiark) and Ultima's is named Altima, a corruption of her name used in the original translation of Tactics. Azem is the only truly original one.

Most of them have played some role in the story, sundered or otherwise. Only Deudalaphon remains completely unaccounted for at the moment.

It's never been said explicitly, but given only Lahabrea, Emet-Selch, and Elidibus escaped Hydaelyn's Sundering it can be inferred they were killed and reincarnated as more limited mortals much like Azem. Using the memory crystals the Unsundered Ascians can restore their sundered brethren to their old station. However, it's not clear whether those restored sundered Ascians are native to the Source; at least Nabriales is implied to not be. Without their memories sundered Ascians could be anyone, so it's nothing to worry overmuch about.

The term "Warrior of Light" is more or less synonymous with the term "hero" in, arguably, most if not all of the shards and Source as a legend spread by Elidibus to help maintain his existence. It doesn't necessarily refer to an incarnation of Azem, Hydaelyn's champion, or a reincarnated Convocation member.

As for Zenos... we still don't have the full picture of what his deal is. He claims to have always dreamed of the Final Days, and Fandaniel asks himself whether Emet-Selch "found a way" when Zenos mentions said dreams. (Found a way to do... what...?) In regards to him being a reincarnated Ascian / Ancient, I don't think that's the case; with it having been revealed the PC is a reincarnation of Azem, as the PC's foil Zenos is much less likely to be the same.