ROTFL!! Ripley was my first thought, too, when I read that. One of my all time favorite movie lines! And yeah, folks will be cheering for Molly in the last movie; the screenwriters will definitely HAVE to use that one!
I hope they keep it in as well. However, I have a sneaky suspicion that if the dialog is there at all, the word "bitch" will instead be substituted with the word "witch."
It is a kids movie after all, and if people on this thread are even afraid to spell out the word as it was used in the book, I can't imagine a kids movie actually using the word.