Yeah, I agree....just don't play.
My sister was one of those who always had to be on the outs with someone. Someone was her best friend (and to listen to her tell it, that BFF-of-the-month person could practically walk on water!), and then a few months later...can you believe what that *#)$*#( did? It was really hard to keep up with her and to know who was in her good graces or not.
And she would change her mind about something to suit whatever mood she was in. Luckily (and I still wonder how this happened), I had her number at a very young age. I had a period of time, like 7-8 years, where we didn't speak. It was blessedly peaceful.
OP, I have to say that it really sucks for you that your whole family is like this, and they essentially 'stole' your daughter and brought her to the dark side. Hopefully, she'll see the drama for what it is at some point. I hope you can rekindle a good relationship with her, apart from all of your other drama-llama relatives.