As far as I know, the Baldurash fix doesn't change any versions of the .exe file and so on. It mainly puts the bunch of files - fixes - into Override folder. So from this side you should have no problems with Multiplayer when you have and others do not have Baldurash fix. The items what each player gets are still given to them from their game, so even if you have the item which is somewhat improved, fixed, it's still the same item as the other player has.
But I guess the best way is to try
Baldurdash patch and multiplayer... 
Linear Mode
