In my ideal summer it would be :
CB1
CB2
Licha (used as 3rd CB, rotations, LB cover etc.)
Tosin (free)
Kambwala (getting the carabao cup starts)
Even if you prefer to loan out Kambwala or would not go for Tosin, then just keeping one of them STILL gives you 5 CB's with each having similar profiles that we don't have to tactically adapt (something ETH supporters cry about to this day since he can only play with his absolute first choice players). Keep the system the same and have the profiles that replace instead of having CB1 and Licha injured and now having to play a completely different defensive style because you're stuck starting Maguire on the left or something.
Also wouldn't rule out Varane returning on a cut rate deal which I'd prefer over keeping either of Maguire/Lindelof simply because he brings more experience and can help lead that room more (don't think he will come back mind you, but with his comments about his body breaking down he might prefer being an elder statesmen at a big club than going to Saudi to be a starter or something).