Download mod allows you to play in 4 (is somewhere in the forum). Add the folder "Data/CharacterCreation" and there put those changed files. Properites.lsx you can edit with the same program that you extracted Main.pak. Path should look something like this: Divinity - Original Sin/Data/Mods/4Player_-_Test_1ddd6993-6d9b-4e71-a437-1195dd217cf6/CharacterCreation (here you put the file - Properites.lsx)/ClassPresets (and here a new modified class if you did it). If you have it correct in the game check out mods.