A reasonable summer/squad is starting to take shape:
ST: Martial, Greenwood, Veteran9
LW: Rashford, James
RW: RW, Chong
#10: Bruno, #10
CM: Fred, McTominay,
DM: DM, Matic
RB: WanBissaka, Williams,
LB: LB, Shaw
CB: Maguire, Bailly, Lindelof, Tuanzebe, Jones
GK: De Gea, Romero
(Garner, Laird, Bernard and Mejbri can handle a game or two presumably if an injury crisis breaks out)
Permanently out: Pogba (be lovely if he stayed), Mata Pereira, Lingard,, Smalling, Rojo, (I'd sell Jones too but with the other CBs going it makes sense to keep him one more year until Tuanzebe is established and Bailly shows some healthy form, and if neither happens we need to buy a CB in 2021)
Loaned out: Dalot, Gomes
Signings:
RW - Clearly the biggest need in the squad.
#10 - We'd be a mess without Bruno, if we sign a RW like Sancho who can also play as a 10 that would be fine, too. Alternatively, we could sign a proper RW and then a player comfortable as a 9 or 10 and not sign a pure 9, but I'm not sure who that would be. Might be best to get creative like Ajax did turning Tadic into a 9, since he could also be a good backup 10.
DM/CM - Again, may not be needed if we keep Pogba or sign a proper AM like Grealish or Maddison to backup Bruno and also start alongside him a lot with Fred or McTominay as the lone DM.
LB - Shaw is good but needs pushing and also when we play 3/5 at the back we need someone to be an assist threat, so this should really be a wingback unless the RW type is someone like Dwight McNeil who could also be the first choice LWB in that setup.
9 - Ighalo is obviously doing well but there are other options. Someone good in the box and in the air makes sense, a loan or a punt on a mid 20s player with the talent and profile who hasn't had a chance yet, like we did with Chicharito, would make sense too. Maybe even the team that takes Dalot can be one with an excess 9 and they send us that striker
and they get a starting RWB in return. There is also the option of just giving Greenwood the job and if need be playing James-Rashford-RW as a front 3 doesn't look so bad.
So, I'd say the minimum amount of moves would be signing Sancho or a similar RW who can also be our creative hub, keeping Pogba or replacing him with a midfielder who can pass, signing a LWB and just trusting Greenwood as the backup 9 (since even if Martial is hurt we still have Rashford who can also play there and we would still haves Sancho, James and the Pogba replacement or Bruno able to play a narrower role out wide) but maybe a small investment on a 9 good in the box and the air like we did with Ighalo.