Actually, it's not Feng Shui, it's the way your family handles things. First of all, your husband's sister is divorced and should not live with you newlyweds. She should go back to live with her parents or rent a house by herself. This point should have been made clear at that time. Secondly, my husband's sister can stay in your house for a few days, but not permanently. She should move out after staying for a week or two at most. You should talk it over with your husband, let him talk it over with his sister and let her leave. Don't mention feng shui, it's sheer nonsense. I don't know your husband's attitude towards this matter. If he also finds it inconvenient for your sister to live in your house, you'd better ask her to leave.
But then again, divorced women are always a little pitiful, and her heart must be full of anger and injustice. Now that you two have taken her to live together, you should comfort her, enlighten her, chat with her more, make her happy, take her out shopping and eat more, and help her through this difficult period, instead of hiding in your room and making your sister feel alienated and left out. At the same time, in the process of chatting, wake her up by innuendo and make her realize that she shouldn't bother you too much and it's best to leave automatically.