Continuity mistake: There is a scene in which a ghost shoots harpoons through the back door of the Mystery Machine. In the next shot, the harpoons are gone, and when the van gets back into the city you see a shot of the back and there is no damage whatsoever. (01:03:20)
Continuity mistake: When Shaggy and Scooby find the "Faux Ghost" ticket, they pick it up and examine it carefully. The Black Knight came and they ran away, dropping the ticket and never picking it up. But when they are back in the Mystery, Inc. headquarters, they have the ticket. (00:22:15)
Continuity mistake: When Daphne and Fred attach the jumper cable to the Black Night Ghost and the 10,000 Volt Ghost, they run away as the monsters explode. We see different shots of the monsters exploding and then we see Daphne and Fred in the corner running away a second time. It's the same shot as before. (01:12:10)
Continuity mistake: When Daphne uses the jumper cables on the 10,000 Volt ghost, she and Fred get blasted away. When they get up, both are covered with soot and ash, however in the next scene when they meet up with Shaggy and Scooby, they are perfectly clean. (01:12:00)
Continuity mistake: After Velma suspects Patrick the Curator of being the evil masked figure, she tripped on the catwalk. She was holding onto one single grate then in the next shot she was holding two, then in the next shot, she is holding one again. (01:15:35)
Continuity mistake: When Scooby puts down all the stuff he found in Wickle's' manor and Shaggy says those are just stuff Scooby wants, the toilet brush is on the left for Shaggy and it's standing up. When Scooby picks it up, he picks it up from Shaggy's left side, while it is slightly lying down. (00:21:25)
Continuity mistake: When the mystery machine arrives at the monster factory, in the courtyard, it is very obvious that Daphne is either not wearing a bra or is wearing a different one than later, when they're all inside the building. (00:44:00)
Continuity mistake: When Daphne is fighting the Black Knight at Old Man Wickles' place, notice that the stunt double's hair is longer and straighter than Sarah Michelle Gellar's. (00:23:30)
Continuity mistake: In the fight scene at the library, you can see Daphne's boots change from stilettos to boots with a smaller heel and back to stilettos again. (00:23:50)
Continuity mistake: When Velma is reading the inscription over the door of the "monster's hive", her hands are behind her back. Then the shot goes to Fred and Daphne with Velma in the background and her hands are down by her side. When the camera goes back to Velma, her hands are once again behind her back. (00:49:10)
Continuity mistake: After Daphne is shocked by the 10,000 Volt Ghost, the ends of her hair are very obviously fried when she's laying beside Fred after she lands. However, in the next few shots her hair repairs itself, without losing any length. (01:08:30)
Continuity mistake: When the gang gets back to the Mystery Inc. Headquarters after searching for clues at Old Man Wickle's, Daphne's boot heels are higher. (00:25:30)
Continuity mistake: When Shaggy gets out of the car on the red carpet, he has a drink in his hand with a straw, but when Scooby drinks out of the cup there is no straw. (00:02:30)
Continuity mistake: C.l Magnus takes the cigarette out of his mouth three times.
Answer: Yes! There was a real Heather Jasper Howe! Like the fake Heather Jasper Howe's True Identity is Jonathan Jacobo! He was arrested with Ned.