No, if there’s no stated difference for upcasting then there’s no reason to do so

Yes! The companions are so good that for the first time in a game like this I could decide on a core party for my first play through. I’ve always been able to eliminate a lot of characters as boring or not my speed, but not in this game. I got as far as the crèche in act 1.5 before I got too frustrated with it and installed a party size mod so I can just bring them all with me