I love companions with clashing personalities and their banter, but will the game only let me choose the ones who, more or less, agree with each other?

That's the biggest thing I fear about companions. That you will have to make a choice between those who more or less agree with one another, or if the balancing opinion between them so they do not leave will mean that you cannot romance one or another. Because it would be a bit disappointing.

I wish they would add more of - rationalize your decisions in camp when you made a choice they really disliked so that you would get more points then you lost with that person, or something like that. I think something similar was in dragon age 1, but it was a long time since I played that game, could be remembering wrong.