Ofc Mohammed is the most common name but thats a name common within the muslim community. I have noticed the name Sarah in every country, regardless of race or religion. Or it might be an abrahamic religion thing but thats most of the world atleast.
I suspect other Abrahamic names might make the cut.
Hard to say. Like, do “Ivan”, “Giovanni” and “John” count as the same, or different names? What about Latin “Amanda” (to be loved) vs. Japanese 愛/Ai (love)? How do we even count this?