So we need a solid 25 man squad, not including U21 homegrown players (Ramsey, Barry, anyone else who may play a part from the academy next season).
Definite squad members next season (13):
ST: Watkins
CAM/Wingers: Traore/Grealish
CM/CDM: McGinn/Sanson/Douglas Luiz
CB: Mings/Konsa/Hause
RB/LB: Cash/Targett
GK: Martinez/Heaton
Probable squad members next season (7):
ST: Wesley/Davis
CAM/Wingers: Barkley/Trezeguet/El Ghazi
CM/CDM: Nakamba
CB:
RB/LB:
GK: Steer
Even if we keep all of the "probable" squad members above, we still have room in the 25 man senior squad for five new players, which should include two full backs and a centre back.
I personally don't think we will keep El Ghazi, Steer, and one of Davis or Wesley, which should open up room for a further striker, winger, and attacking midfielder.