There is a couple options imo :
1) I've always been a believer that Bruno Fernandes should start a little deeper with the free ability to get forward; a bit like Iniesta was a CM/CAM. The reason I say this is because Bruno Fernandes is hardly sticking and waiting for the ball at CAM like he was ozil - if he doesnt have the ball you will see him running to CDM positions before running all the way back to play in ST positions. He knows how to run and find half spaces before the defenders do (because he does it already after he runs down to CDM) so I dont really see what Bruno as a CM cant achieve.
2) Pogba is currently used as our deep lying playmaker either in a double pivot or a 4 man diamond. When he plays in a double pivot he seems to be able to make long distance passing in the squad best. However when we play a 4 man diamond he can mix it up and get forward and be the player that spreads the ball channel to channel.
What I hope Rice does is provide that defensive balance that Pogba sometimes feels in a 4 man central diamond, where he has the ability to get forward whilst making passes from deep. Matic and Pogba looked like a good but aged combination when Ole was testing out his midfield partnerships(which ended up with scott and Fred) and Rice should be able to pull Matic's performance up even if Pogba is stuck in a double pivot. I'm rather hoping that Bruno and Pogba are in a CM/CAM partnership like Silva and De bruyne were guarded by Rice/Fernandinho.
3) Finally there is Van De Beek. There is 2 places he can play. If we played a midfield diamond, then Rice can cover a midfield partnership of Bruno & Pogba whilst VDB plays as a shadow striker/false 9 type player. Alternatively, Bruno & VDB could swap so Bruno plays as the forward and VDB as a CM/CAM next to pogba giving our CM a mix of quick short passing (VDB) and accurate long passing (pogba) guarded by Rice.
The last thing with VDB's future is that he might end up being CM with a quick short pass-rush to space- short pass - rush to space type player which could end up slightly like a tempo setter to the team in the middle of the park; however he will need a player like Bruno Fernandes deeper to pass the ball back to him and make the through balls that VDB has yet to show is within his locker.
Garner is also someone I dont expect to go on loan again especially if we buy Rice as he gives us that deep lying playmaker type ability in the squad even if he is too young to make an impact that season. If players like Diallo and Hannibal are with/near the first team then I dont see why Garner wont be.
Mctomminay will have the ability to play as a pure box to box player that gets forward and scores long distance goals as he has done with Rice behind.
If we play a top top team and need to get defensive with man marking then we can go with Rice and Fred or Rice and Mctomminay or back to Fred and Mctomminay as a partnership to keep us defensive.
I value Rice alot for being a young ball winning midfielder whether its mascherano or an old school less passing Busquets in the way he can hold a teams positioning by his defensive ability. If we need a deep lying playmaker then that's more about replacing Pogba in my eyes.
433 -
Pogba- Bruno
Rice
Or
Bruno -VDB
Rice
4231 -
Bruno
Rice Pogba
442 diamond
Bruno
Pogba- VDB
Rice