Cassiopeia Musca Tonks

Edward dumps Bella. Bella didn't tell him she was a witch she is actually Cassiopeia Musca Tonks. So she returns home to England. And the Sunrises on her and Harry's relationship. What will happen when the Cullen's come to Hogwarts? As she is part of the golden quadrant ever if she was a 5th year Ravenclaw...