I hope there are different companions to choose from at the beginning. I'm A-Okay with having pre-made companions, but I'm definitely not okay if I have to play with the same 3 every single time; that kind of makes it so the game has zero replay value to me.
From what I've gathered, there will be as many companions as there are origins, minus whatever origin the player picks. So if there are six origins, you'll basically have 1 and 1/2 playthroughs worth of new origins. It'd be incredible if there were eight different origins, so you'd have basically two fairly unique playthroughs, but that's asking a lot.