If we get even closer to Garlemald proper, Chemist as some kind of magitek-based healer could be likely (but I think it could also work as some kind of Thavnairian salvemaker, too, there are a few ways Chemist can be interpreted to fit well into FFXIV). It feels doubtful we'll get Geomancer at all because I think there was a lot of emphasis on it as "this is just an Eastern hybrid of conjury with principles of astromancy".

Did anything ever happen with that Onmyouji/Mystic job concept I recall being shelved to do SAM/RDM as fan-demanded jobs instead? That could be a possible caster DPS if they bring it back.