Need a way to remove others gravestone, as an admin/OP ofcourse.

Thats a good point. How do you think that should be done? How about RClicking with an empty grave finder (accessible only through creative menu) on the grave by an admin?

Yeah that would be great! im sure there is a way to do it now, since its an entity with something like this: /kill @e[type=something something] but thats just not a viable solutiont tbh.

but yeah the empty grave finder idea is good