Other mistake: When Russell Hammond goes to William's house he spots a professional photo of William and his sister Anita. The photo shows William as a 15 year old with his sister. But Anita has been away working as a stewardess, and has not seen William since he was 11 - who was played by a younger and different actor in those scenes.
Other mistake: In the intro to the Pastoral Symphony, the narrator identifies the deity who cloaks the world with Night to be Morpheus, who is the Greek god of sleep and dreams. However, the character in the animation is fairly obviously female, with long hair, eye shadow, and lipstick. My theory is that the character was intended by the art team to be Nyx, the Greek goddess of Night. Night would be a more likely candidate to be making it nighttime across the world, while Morpheus would be more likely to put people to sleep or send them dreams.
Other mistake: In the scene where Paolo leaves the stage after everyone discovers that he can't sing, his bodyguard Serge stops him and Paolo suddenly loses his Italian accent. Paolo sounds very American when he says "You work for me, Serge."
Other mistake: In the scene were Patrick breaks the car window, when he walks to his seat you can see a point of red light (like a laser) on his back. (00:40:45)
Other mistake: In the 'Macavity' dance, Demeter makes a mistake with one of her moves and makes an "Oops." face.
Other mistake: After the on-board announcement that the plane is at cruising speed and altitude, the exterior shots still show the wing flaps extended for landing. Due to structural limitations and the extra drag created, the flaps cannot be used at higher speeds.
Other mistake: Carolyn Stilton shoots Blondie O'Hara in the head and is lying dead over her dead husband. Just before the final scene starts she begins to open her eye.
Other mistake: When Apollonia is smacked in the face by the Kid after announcing she's joining Morris's group, she falls into a dresser and knocks all the magazines off the top of the dresser on to the floor. When the same scene is replayed during the 'When Doves Cry' sequence, the magazines don't fall to the floor.
Other mistake: During one of the recording studio scenes, there's a short segment that shows a bunch of VU (audio level) meters close up. The very first meter in that sequence is not a VU meter. Its from of an old HF (High Frequency) Amateur Radio transceiver; The scale is marked for RF, SWR, and ALC. I'm suspecting that someone involved with the post production editing is a Ham.
Other mistake: Watch when two bodyguards shove Mel and Val towards the car at the end of the movie- one of the bodyguards steps on Val's tail and nearly trips.
Other mistake: When Whoopi first takes over the choir, she asks the sisters to stand according to their singing voices. She asks where the sopranos are, and several women on opposite corners of the grouping raise their hands. She asks them to all move over to the left group, but only one of the two women on the right side actually does so.
Other mistake: On the first day of the Big Bounce, during the dancing, a white towel-like object is dropped on the floor and in the next shot it is gone.
Other mistake: When Jordan Cahill sings on the porch of the old house, he is holding the guitar but he is not actually playing it (he's not really fingering on the fingerboard).
Other mistake: When Paul is making the DVD, there's a record of Terri performing a song she wrote(One more mile to Jericho). At the very end, outside the school the kids start play some music together with Terri singing. That's supposed to be some random thing like it was before, but actually they play and sing Terri's own song. How come?