I'd rather have Varane than Stones. 40-50m that is talked about for Stones would surely be enough to lure him away from Madrid. And a young solid French CB pairing (with Laporte), that's 7-8 years of central defence sorted. If potential and longevity is something we can't afford now, I'll definitely love to see Leonardo Bonucci, 29 y/o probably has 3-4 years of top quality football left in him. His ball playing is criminally underrated, certainly on par with Pique, Boateng,Hummels etc.
Latter is probably more of a wishful thinking, but if we are seriously interested in another CB (considering Laporte deal is a matter of when and not if) then the first option is what I'd personally like to see happening.