I agree this is how the so-called "camp followers" will function. But that only makes them NPCs that accompany you on certain quests because the quest requires it. I doubt we will be able to use them truly in the sense of a companion who you can freely add to your party whenever you want.
Maybe. Maybe not. I can’t think of a good reason why a camp follower shouldn’t be able to fill in a slot where you could put a mercenary. Then it’s just a case of how much dialogue to give them. Possibly you wouldn’t be able to take them for certain core missions?
In any case, none of this helps me. I will only use fully fleshed-out companions as my party companions. Any others would be unacceptable to me.
I’m not sure anything will help you enjoy the game at this point going by your previous posts. But Larian might be able to help other players with a less broad range of concerns.
As I see it, the story has to be designed around a group of up to 4 “heroes“, not one hero with an entourage of friends to allow multiplayer to have the same story. It’s no coincidence that DOS had 2 main characters (2 player multiplayer), and DOS2 had 4 (4 player multiplayer). Similarly, BG3 needs a story for up to 4 main characters. While it might be possible to have one hero and a gang of followers for single player, there’s a good chance this might make the story less meaningful (we won’t know until next year).
But a core group of 4 heroes and bunch of other people might be more viable.