I think our best side looks something like this. Plausible back-ups in parentheses.
GK: Pickford (Robles, Stekelenburg)
RB: Kenny (Coleman starts when fit)
CB: Holgate (Keane)
CB: Williams (Jagielka)
LB: Martina (Baines starts when fit)
DM: Gana (Schneiderlin, Baningime)
CM: Davies (McCarthy)
CM: Rooney (Barkley if he ever plays again)
LM: Bolasie (Sigurdsson)
CF: Calvert-Lewin (Niasse)
RM: Lennon (Vlasic, Lookman)
I think we can safely get rid of the following:
Mirallas - Should never have been re-signed.
Besic - Needs too much work, won't see enough games to get to an appropriate level.
Robles or Stekelenburg - Not that anybody is interested.
If we get a significant offer, I think we should sell:
Klaassen - I don't see a role for him. He does some clever things in the final third but he's too passive overall. Our midfield struggles during build-ups and I don't think we have room for someone who doesn't really show for the ball.
Schneiderlin - It would be a slight risk w/r/t squad depth but if some PL club is willing to pay good money for a "proven" player, we should take it and run. I was a fan of his in the past but he looks awkward in every configuration we've seen this season.
Sandro - I don't think he's actually a centre forward (https://differentgame.wordpress.com/2017/07/04/the-data-scout-sandro-ramirez/
), I don't think Allardyce knows what to do with him, and I don't think he's settled in England at all. There's no shame in making a profit, even though there might be a good player in there.
And we should probably loan Lookman if there's a mid-table Championship club willing to let him play through his mistakes.