hajime-isayama-official answered:
Did you just ask me if I know Harry Potter?!
Gryffendor: Eren, Levi, Mike, Jean, Sasha, Historia, Reiner
Slytherin: Erwin, Mikasa
Hufflepuff: Marco, Connie, Bertholdt, Nanaba
Ravenclaw: Hanji, Armin, Ymir, Annie, Moblit