A non-playable no-tadpole companions is something I would have a great interest in, but I think it would put the entire origin concept into question - mostly, how would it work in coop. I think it is safe to say, that origin system’s biggest advantage is for coop companions being able to join you at any moment and take control of your companions. Would they still allow for that for non-tadpole companions? If those companions have added content to make them playable, why not make them origins? Don’t they need a wide range of playable origins to choose from, before entertaining an idea of non-tadpole companions?
And as Minsc is confirmed - what will be his role? Companion? Follower? Quest NPC?
Killing “spare” companions would be in line with D:OS2 formula.
Yes - the problem with non-tadpole party members is how would they be treated in dialogue. There are some conversations, such as the goblin priestess, that would require completely different player and NPC dialogue for a tadpoleless character.