Sorry not sorry that you need to be told this: sansa is not a bully to arya, infact she was one of arya’s biggest ass-coverers in agot. While ned was busy ignoring his daughters and couldn’t be arsed to control his wild child sansa was more a parent to arya than their actual parents. If sansa had been a bully she would’nt have looked out and covered for arya’s manner less behaviour as many times as she did.