I'm dying to see his dialogues with Astarion! However Minsc romance?
Assuming Minsc is actually in the game, I hope he's a unique type of companion that can't be chosen as an Origin character or romanced. Minsc is the archetype follower, not a leader. I just can't imagine him leading the party. Especially if the MC has an option to take the evil path with the tadpole. That's just not Minsc.
As for romance, I dunno... it would feel weird to have an iconic character like that eager to jump in the sack with the MC. So I hope he's a unique companion choice with some limitations that preserve his BG archetype.