So, my thoughtson the rest of the transfer season:
Clapham comes in to replace Caceres.
We then need to find a youth player to replace Costa, hopefully a young striker.
We then find Mully's replacement in the squad (difficult I know) and this is where we can make big improvements on last year. An attacking midfielder would be good, someone to play in the middle and offer something different to Timmy. Another striker could be a good option as well, and this means our youth player could be used up elsewhere (like wingback cover).
That would give us 20 players unless someone has a great World Cup and gets picked up overseas. 20 is what we want given we don't have a reserve team.
Edit: Oh and someone to take Ferrante's spot. How could I forget about him?
1 On the way

2 This is what we've lacked in forever.