To make a long story short with this post, we've already had three guest star characters for three of the show's main characters with Weird Al as Cheese Sandwich for Pinkie Pie, Lena Hall as Coloratura for Applejack, and Patton Oswalt as Quibble Pants for Rainbow Dash's. So I just have one question for you all: Who would you want as guest stars each of the other three Mane Six members I didn't just mention; Rarity, Fluttershy, and Twilight? (I don't count John de Lancie as Discord for Fluttershy since he was obviously introduced before Keep Calm and Flutter On and is far more of a semi-regular than he is a guest star)
I got a model guest star for a character for Rarity like Charlize Theron for an idea (since Oswalt is the first not to be in a musical episode for one with a guest star), but I'm not entirely sure about Twilight and Fluttershy yet...