Revealing mistake: Right after "Without Love", we see Edna answering the phone. If you've seen the movie as many times as I have, you'll see that this is a recycled shot from earlier when Mr. Pinky calls.
Revealing mistake: During "You're Timeless To Me," It shows the house lights on. In the very end of the song, when Wilbur blows out the candle, it is pitch black, but the house lights should still be on.
Answer: Yes, that is Ricki Lake, the original Tracy Turnblad, in a cameo appearance!
Movie_Freak 1