I think a lot has to do with the boos and that Charley felt she was in her way close to Shabz.
OR it may be that one or more of the men has said that he heard "Get Charley Out" chanted as he came in?
She also knows Brian doesn't she? There is a combination of reasons for her change.
As for the other girls. There is a nicer balance and having four new people come in at once whether male or female means more people to chat too and get to know. It means they do not have to talk (or argue) with the same old faces.
This is my opinion and I have a huge head with a gigantic brain plus I am female so normally right
