"We are coming from the place, from where you are."
Translation:Onnan jövünk, ahonnan ti.
Onnan jövünk, ahonnan ti, means "We are coming from the [same] place you are [coming from]." I can tell that the missing verb in the second part of the sentence is "you are coming" because they have ahonnan ("whence" or "from where") rather than ahol (simply, "where").
Unfortunately, their English translation is not so clear about this.
If you want to make a similar sentence to say "We are coming from the place where you are [located]" then you could go with Mi onnan jövünk, ahol te vagy (from there .... where you are).
So ...ahonnan te vagy (something like "whence you are") is a little weird, not because of the pronoun, but because of the mixture of "whence" with a static word like "are." It could possibly be understood as "from whence you (originally) are" but there are other ways of expressing that.
I almost wrote no, but yes, you actually could say that. But note that in Hungarian "to be from somewhere" is very rarely expressed as "lenni valahonnan." You should use the adjective "való" (it also has other meanings, "appropriate" "real" come to my mind, I can't tell if there are others) or the verb származik ("originate", used rather widely) or some other words.
I think the creators meant that "are" at then end to belong the the present continuous tense. So the original translation means "we are coming from the place where you are coming from" while yours means "we are coming from the place where you are from."
Here's an example when "valahonnan lenni" is definitely correct, just in case other Hungarian speaker can't think of one off the bat: A székek a boltól vannak.
EDIT: You could say "Onnan jövünk, ahonnan ti jöttök." with no porblem, of course.