He's doing a very good job at right back, why mess around with that right now? He's better defensively than Lowton so I wouldn't change that going into the Albion game. It's an option in home games like Sunderland though.
Personally I don't think Bacuna is ready yet for a midfield role. I think he is better playing at the back where everything is happening in front of him and he can attack into the area in front of him. I don't think he has developed the vision to be a decent midfielder and gets caught in possession too often.
If Gabby's out I'd play Weimann jus off Benteke with a 4 behind of Bacuna Delph Westie and Tonev. Lowton right back.