It is NOT based on approval at all. I have very high approval with Astarion and neutral with everyone else (never use any of them) and after 3 times playing through the game I still didn't get nearly half the camp cutscenes with him... it seems everyone is overriding him. It is beyond frustrating that I'm forced to NOT recruit anyone else so that I can see all the scenes with the only companion I'm interested in. I really hope it will get fixed soon. Dragon age implemented it rather well, aside from the cutscenes you also get to hear an input to any important moments in the game from all the companions in the party.
I also group with only Astarion most of the time because I want to see his reactions the most. Why can't every companion react after the tadpole dreams, after learning of a way to treat the tadpole, etc.? Why must Shadowheart always get priority at camp and why can't more than one companion have a scene per night at camp? People talk about limiting long rests and I don't want them to because I already have to rest too much just to get the other companion scenes over with to get to the ones I want.
If I'm not doing that, I'm killing companions or dismissing them and racing to beat them back to camp so I can hopefully see someone else's scene. Which is a tedious and frustrating way just to get Gale's Weave scene to trigger before I've explored too many zones and locked myself out of it. It's like a juggling act where I have to meticulously metagame and not let things unfold naturally as I play, because that would make me miss half the companion content.
