I do remember them saying (again, can't recall where) that apparently near the end of act 1 / start of act 2 that you'll be able to do a "respec" on your characters. There was a thread asking about details here on the forums, but that's about all that's known is there IS an option to "rebuild" the characters IN GAME. The question of course is at what point and what requirements there are to unlock the "respec" option.
As to the 4 player as 1 player ... keep in mind that is likely not what they intended and it may very well break certain "flags" in the game when you would otherwise MEET the characters normally.
But if you insist on trying it, there's a youtube video of how it was done (of course it was done during alpha so they might have already removed that option for release).
And yes, I do agree that auto-levelling their stats based on your level DOES suck. I hope they make a patch to change that. Because it can be painful if you don't get all the companions as quickly as possible.
