Bridget Vreeland played by Blake Lively attends Brown University. Another of Blake's characters, Serena van der Woodsen from Gossip Girl (2007) is planning on attending Brown University at the end of the second season.
Julia is first seen dressed on stage as Marie Antoinette, saying "And treachery in me, your queen." In the gag reel, she says "Your weak mind sees rot" as an extension of that scene. A Google search turns up nothing on these lines beyond references to this movie, so it seems that this was not a real play but simply made up for the film.
In a deleted scene, Carmen ineptly attempts to "interpret" between English- and Greek-speaking people by speaking only Spanish. This explains why in the next scene (which remains in the movie), Tibby says to Carmen, "Oh, so you speak Greek now?"