future zamusa is most likely present zamasu that used a time ring (whenever he completes his plan) thats how he remembers goku and why he ain't need to fight trunks' goku. tho him jumping to not only a different universes timeline but a alternate one is iffy. unless time rings work in every universe regardless of if its your home one then ok , but how wld it get him to trunks alternate future and not the main dbz one'
![patrice :patrice: :patrice:](https://www.thecoli.com/styles/default/xenforo/smilies/patrice.png)
(his universes green rings wnt work cuz their specificall tied to that universe unlike time rings and i doubt he stoe them from uni 7's kais so...)