"Are you here, too?"
Translation:Ti is itt vagytok?
It is not unnatural, but it means something else. Mostly in questions. Are you here, and also there? "Te itt is vagy meg ott is?".
Or, with a specific intonation, with a big emphasis on "vagy", "Te (már) itt is vagy?" is a question of surprise, meaning "You are already here???".
Basically, the word "is" (also, too) refers to what is immediately in front of it. So, in "te is itt vagy", it is "you too". In "te itt is vagy", it is "here, too".