"The autograph" girl, is Kessia Randall, the real-life sister of Ethan Embry (Mark).

Ethan Embry's (Mark) brother, Aaron, is also in the film, as an uncredited mosh-pitter.

Just after Lucas tells Joe he's a 'superb manager', Joe drags him off to beat him up in his office.  When he takes him into the back, you see a girl standing in the doorway.   She is the same girl you see when Mark and AJ enter the store at the beginning.   Her character was called Lily and she was cut out of the film.  Her name is also still in the credits.