I'm pretty sure Tzelanit meant that Divinity 2 (aRPG, has one protagonist) is not the same as Divinity: Original Sin 2 (has origins).
I really hope they manage to get some subclasses from Tasha's. There's bound to be a lot of cool stuff, including reprints from setting-specific books. For psionic options specifically... idk, I like psionic flavour, but I saw them as Unearthed Arcana and didn't like the psionic die mechanic at all. Iirc WotC have said it'll be changed, so maybe I'll like them. Still salty they've changed flavourful Abberant Mind to a generic Psionic Soul, though.
Regarding your OP: all the (current) companions are going to be playable, just like D:OS2, however you won't be able to change their class. (Or subclass if it's level 1 subclass like Cleric's or Warlock's.)
