I would probably go for Pogba, Fred and Bruno most of the time. I think having Fred's work-rate is crucial alongside Pogba. McTominay works hard too but I feel Fred is exceptional in that particular aspect.
The issue is it's not the most positionally convincing partnership to be holding the fort in front of the defence when we are under pressure. It also has the same problem as every other combination we have when Pogba plays there, which is that Pogba has very limited scope to impact the game higher up the pitch otherwise our build up leaves a lot to be desired.
I'm not so convinced that Rice answers the problems we have. I do think he would improve us, but for what West Ham would demand, I don't really see it as a sensible option. He looks a good footballer, physical, decent PL experience, can pass a bit, but he has plenty of games he doesn't get on the ball enough and is fairly quiet. It's okay having those anonymous outings for this West Ham side but to ask him to come in and link our play seems a massive ask to me, I think he's some way off that. Admittedly it's not as if many options are immediately coming to mind but you'd have to be pretty certain Rice is the answer due to the scale of that particular deal.