"Are you a singer?"
énekes vagy? (informal) would suffice. Ön énekes? (formal)
If anyone else wondered why 'Te énekes?' doesn't work, it's because it would translate to 'you singer?', making you sound like a somewhat cultured caveman :')
The formal form works differently though, and 'Ön énekes vagy?' and 'Ön van énekes?' or 'Ön énekes van?' all make no sense; the only way for the for the formal to work in a sentence like this is to just have formal pronoun + noun + question mark
Formal / informal is and likely will be a very difficult aspect for this aging brain.
It is not 3rd person, but one of the polite forms of 2nd person. 2nd person singular may be te (informal), or maga or Ön (formal). I don't think Duolingo uses maga much if at all. The formal ones, although they are 2nd person pronouns, do use the 3rd person form of the verb, when there is one.
Thanks I don't recall seeing any discussion to this point about polite/impolite forms so that is now clear!
yes, adding nő (woman) as a suffix to a job can show it is a woman. énekes = singer /énekesnő = woman singer
tanár = teacher / tanárnő = woman teacher
színész = actor / színésznő = actress