Presumably one in is an academy type. 25 man squad I'd see like this next year:
Cavani, Martial, Greenwood
Rashford, RW, Diallo, James
Bruno, Van De Beek
DM, Fred, McTominay, Matic/Garner
Telles, Wan-Bissaka, Shaw, RWB, (Williams/Dalot)
LCB, Maguire, Lindelof, Bailly (Tuanzebe)
De Gea, Henderson (Grant)
So 6th midfielder could well be Matic again if it ain't Garner, but hopefully instead of just plugging in Matic/Garner we would look more to play 2 up top (Martial drops deep anyways and Greenwood and Rashford aren't really lone strikers so not a terrible idea) or 3 at the back (shaw is comfy at LCB).
Starters are in Italics, but I don't see Cavani or Martial as first choice if we do sign a RW, more of a horses for courses deal since they're so different and hopefully Greenwood passes them both and has his first 20 goal season anyways.