I agree with your Number break down. Just not on all the players. But definitely want Maffeo back. And I'd rather have a leftie play leftback.Nah. I like Zinchenko but I both don't think he's a very good LB and that the position hinders him from playing his best stuff. I'd have him in the squad as an attacking utility player.
I think the senior squad should be made up of the following:
2 GK, 4 FB, 4 CB, 2 DM, 4 AM, 5 FWD = 21 players + defensive utility + attacking utility, leaving some room from a 25 man squad for youth players to get a chance.
With our current players, I'd have that as: Ederson, Bravo/Walker, Mendy, Danilo, Maffeo/Laporte, Otamendi, Stones, Kompany/Fernandinho, Toure/De Bruyne, Silva, Gundogan, Bernardo/Aguero, Jesus, Sterling, Sane, ???/Delph/Zinchenko, with the guys in italics likely to be considered in the summer (potentially Gunn, Fred and Mahrez, say).
As for Zee, I think his chances of success as a Midfielder for us are slim. He'd be just good. An inferior mix of Kev and Dave. But he has world class potential at LB in our system or Napoli's.