I have a feeling that the sorting hat would be able to put her in all houses but Hufflepuff, but I think it'd narrow it down to either Slytherin or Ravenclaw. Taking in Gaga's personal opinion on the matter, I think it would ultimately sort her into Ravenclaw.
You should do more artists and just change the thread title. It would be interesting to see where everyone's fave is. And for a stan site there has to be a sizable enough Harry Potter fandom population to keep it going.