Trivia: When King Triton enters the concert hall and passes over the audience, you can see Mickey Mouse, Goofy and Donald Duck sitting among the audience. (00:03:33)
Trivia: In the scene where Anna is outside the gates during "For The First Time in Forever", you can see the backs of Flynn and Rapunzel from "Tangled".
Trivia: In the closeups of Goob on the baseball field, there are two billboard advertisements on the fence behind him - one is "Jungle Book" featuring Mowgli with Baloo, and the other is "Toy Story 2" featuring Woody, Jessie, and Bullseye.
Trivia: A little nod to another Blue Sky Studios Production, "Ice Age". When Rodney is looking around Robot city, he comes across a red robot that plays hip-hop. As Rodney walks away nervously ("Uh, n-n-never mind"), pause the frame just before the shot changes and you'll see (on the left) a yellow, mechanical Sid. Sid is the sloth (and the main character) from "Ice Age". (00:15:25)
Trivia: In the waiting room of the dentist's office you can see a Buzz Lightyear action figure lying on the floor. (00:25:35)
Trivia: In the Fairy Godmother's workshop when Shrek dumps the cauldron of potion over the employees, two of them are transformed into Lumierre and Cogsworth from "Beauty and the Beast" (1991).
Trivia: When the Sultan is idly building a tower of miniature animal figures, one of the figures is the Beast from Beauty and the Beast. Also, the king crab the genie pulls out of his cookbook is Sebastian from The Little Mermaid.
Trivia: Susan Bones, who was sorted into Hufflepuff, is shown prominently throughout the film, even in some of the Gryffindor classes. The reason she is used so much is that she is actually Chris Columbus's daughter, Eleanor.
Trivia: Eric Stoltz was originally cast as Marty. After filming quite a few scenes they realised his acting style was too dramatic for the humor desired, so they cast Michael J Fox (who they couldn't originally get because he was busy with the TV show Family Ties). Filming was on weekends and nights around his TV schedule and using his double at other times.
Trivia: In the beginning of the movie, when the candy store owner is singing the candy man song, there's a spot towards the end of the song where he lifts up his counter to let all the kids in. Watch the little blonde girl as she gets walloped in the chin by the counter. (00:04:30)
Trivia: The two old men near the end, talking about it being "old school" are voiced by Frank Thomas and Ollie Johnston, two Walt Disney animators who worked on such classics as Bambi and Cinderella.
Trivia: When the taxi Jessica and Eddie are in hits the lamppost, she spins around and her dress shifts position. For a couple of frames on the laserdisc version her underwear vanishes, or at least it appears to. Opinion is divided as to whether it's a deliberate move by the animators or just an error in colouring. (https://www.snopes.com/fact-check/who-stripped-jessica-rabbit/). (00:18:15)
Trivia: In the beginning of the film, young Sonic gives Longclaw a flower with spiky petals. This flower is actually based on a flower sprite from the original "Sonic the Hedgehog" video-game for the Sega Genesis. (00:02:16)
Trivia: Right before the camera shows Kevin walk up to Mr. Duncan to pay for his things, it shows a man and his baby. The man is really Chris Columbus (the director of the movie) with his daughter (Eleanor Columbus) who later played Susan Bones in the first two Harry Potter movies.
Trivia: Miley Cyrus has a brief cameo at the end of the film in the musical number "All For One". She is seen in a quick close-up, wearing a yellow top, dancing with other people on the rocks around the pool.
Trivia: When they power-up the Death Star, the control panel is a Grass Valley switcher, production equipment which is still prevalent in television stations everywhere.