Maguire needs replacing, perhaps on a free he'd be a canny signing as 3rd / 4th CB.
Varane is injury prone and Shaw (good as he is at LCB) is one of two capable LB's. Unless Fernandez or Williams are part of the squad next season using him as 3/4th CB and first choice LB seems a bit tight.
No idea how good Skriniar is these days mind you. He looked solid 2 or 3 years back.