Larian Studios Forums Divinity: Original Sin 2 Divinity - Original Sin 2 - General Early game companions

I also agree on the fact that if you would like to do things with less characters you should earn more XP.
XP should be a fixed amount to be split, so scaling up if you have the same group level but less characters involved. This way you can choose to go solo, have harder times but gain faster progression or go with 4 pple, easier fights but slower xp path.