I actually enjoyed this episode even more than the last one! It was funny and very touching in parts. I find her best friend odd, one minute she acts like a fake bitchy friend to her, the next moment she seems to be really genuinely rooting for her. That said, a lot of teen friendships can be a hotbed of fickle bitchiness, so it portrayed that well.
I thought that too. It was hard to tell where the friends loyalty truly lies. I think they were lifelong friends that are starting to grow apart. Her keeness for Rae to attend the pool party seems to me to be both friendship and the old story of "having a fat friend there to make you look thinner"