A live-action sequel was proposed, and a preliminary script was drafted, when production wrapped. Unfortunately, the movie was a box-office disappointment, despite grossing more than $100 million in the US. Christina Ricci and Bill Pullman were attached to other projects, and would not be available for more than a year. The producers decided to produce a cartoon series instead.
When Dr. James Harvey is rolled down the stairs in the carpet, he starts with his head facing towards the stairs, but lands with his head facing the other way.
In the classroom, Casper ties Amber's shoelaces together before anyone else's. When Amber stands up to protest the party being at Kat's house instead of hers, she doesn't trip over them. She sits back down, but when the bell rings and she gets up, she trips.
Amelia Harvey: James, I know you have been searching for me, but there's something you must understand. You and Kat loved me so well when I was alive that I have no unfinished business, please don't let me be yours.
Stinkie: [the Ghostly Trio along with Dr. Harvey are out partying, and Dr. Harvey is drunk, singing karaoke]
Hey, this Dr. Harvey's got a lot of spirit, you know what I'm sayin'?
Is it true that this is connected to the Ghostbusters films?
A
Yes. Dan Ackroyd makes an appearence as founding Ghostbuster Raymond "Ray" Stantz about 8 or 9 minutes into the movie. He's the guy who runs out of the mansion with the proton pack saying "Who you gonna call? Someone else."