Well, we kind of figured it out. Setting the max to 4, and joining in the 4charactercreation mod you suggested - sadly it wouldn't work together, we would get crashes when someone would join the game.
However, luckily the first two companions were practically set up the way two of ours wanted, so we customised the main chars to the rest's liking.
However not a fix for people who don't like the companions' setup, but for us it worked! Which practically means that if other modders make a world, 4 people could play like that - as long as companions are added customizeable
