If everyone in OP leaves our squad is:
DDG, Heaton (Grant)
Dalot, AWB, Telles, Shaw
Maguire, Lindelof, Varane, Bailly
Matic
Fred, McTominay, Pogba
Bruno, Mata
Elanga, Rashford, Sancho, Cavani, Ronaldo Greenwood*
So 22 players, 23 including Grant, which is about right, although the Greenwood news maybe leaves us an attacker short so maybe Lingard will stay.
Ideally we obviously need a proper DM too, and Mata and Matic need replacing too but that will likely happen in the summer.
There's a few promising youngsters as well who could come into the equation if needed (although admittedly those closest to 1st team are out on loan). I guess of the youngsters not out on loan, Mejbri and Shoretire are closest and I wouldn't mind them getting a game or 2 in attacking positions, but I'd be a bit worried about an injury crisis to defence or central/defensive midfield.