I use different companions in each camp.... They've been awfully silent in the western approach. They only talk when i do some side quests, the darkspawn one now. No banter between them.
Will try the hissing wastes soon.
In Hissing Wastes, I've heard 2 banters between Sera and Cole. 2 banters between IB and Cassandra (one of which was on my relationship with Cass.) A few banters between IB and Sera. I can see the friendship blossoming and I believe this was the first time I had heard one of their banters. I haven't tried any others that got a banter yet but I'll keep trying. I've turned my game down to casual now that I have got the trophy for Nightmare. God it's so much easier. So now, I'm just running around with any party combo I feel like. 4 warriors is fun.
Oh, and 2 between Viv and Sera. Something about Viv getting revenge on Sera. It's kind off funny.