idk tho because Eurus killed Victor so then if Victor was John then John would have never existed!<<<no they're not thinking of it literally but in a metaphorical sense. Victor looks so similar to John and must have reminded Sherlock of him.
All infinity stones revealed by Marvel Cinematic Universe until Age of Ultron/ oh and I was looking for a chart like that one. With all the infinity stones and their locations. I think the last one is at the Eye Of Agamoto, in Doctor Strange's pendant.