I agree that we generally treat "who" as a singular, but we do use plural verbs when we know that "who" is definitely referring to a plural. For instance, I might say "I know who the Chief Justice of the Supreme Court is, but who are the other justices?"
Who are the other justices - grammatical
Who else are the other justices - ungrammatical
'who else is there'= also accepted now.
I'm not changing the current translation (for now), because I think that by changing the translation, this thread will be deleted as well.
Was taking to my driver (Good thing I got one that speaks English) and he said "siapa lagi ada di sama" would also be correct which is how I would translate the reverse.