I think a lot of this depends on a) where we finish and b) how well 4-5 players acquit them over the course of the rest of the season.
*If* Olsen continues his vein of form, claims the #1 GK spot, and remains a calming figure at the heart of the defence, and if it comes down to trade-offs within certain positions, it may be wiser to invest heavily in a top wing-back and winger who'll transform the right-hand side for us.
Right-back and right-wing are two of the glaring necessities at this point, preferably young talents (20-24) with a high ceiling à la Godfrey, who will come in for a decent fee but manageable wages.
*If* we can ease Gbamin back into the team by the season's end, then we're fairly well placed for backup in defensive midfield; *if* Gomes can successfully shake off his post-injury rustiness and hit a rich vein of form then we could be fairly well-stocked.
*If* King does prove to be a versatile option for the three forward positions, then maybe only one top wide forward option may be needed (which will no doubt require considerable outlay).
Equally, *If* Kean suddenly decides he's willing to come back and stake his claim at Goodison in the summer, then perhaps between DCL, Richy, himself and King we may have sufficient cover at CF.
And then *if* a couple of young players can step up and prove their value as squad members (Gordon, Onyango, Branthwaite etc.) then it allows us to move on Bernard, Sigurdsson, Delph etc. and replace them with younger players with considerably lower outlay on wages.
So. in conclusion, RB and RW are absolute essentials this summer and then depending on the performances and personal circumstances of the aforementioned players, we should perhaps look for additions at GK, CM, CF as well.