Edo Tobirama seems to have a mystery listed but I can't figure out what ninja is needed to activate it. I tried Hashirama and Hiruzen but nothing, can't test Edo Hiruzen or Edo Hashirama since I don't have them yet. I am wondering if they added it to the game, but forgot to actually enable it?

That is sort of what I was worried about, was really hoping it would be triggered by normal Hashirama. O well, looks like the wait will continue a bit longer. Thanks for confirmation.