Larian Studios Forums Divinity: Original Sin 2 Divinity - Original Sin 2 - General lone wolf with 3 player party

So you are talking about 2 players and not 4? In that case I guess, it will work for you. As long as you don't control an NPC. At least in D:OS1 it worked that way. You could go lone wolf playing with one character and your partner not playing with 2.

A 3 player party is something different than 2 player + 1 companion.