Visible crew/equipment: When Beetlejuice is first introduced, right before we see him, the camera rotates around the model and the sign above the grave lights up. Right before the sign lights up, you can ever-so-subtly see a part of the camera's shadow move over the model. It's subtle and easy to miss, but once you see it, it's pretty obvious.
Continuity mistake: When Trevor is checking for the black mould, the fan next to Phoebe is facing the far right side of the room. An instant cut later, it's facing the far left side.
Continuity mistake: During the "One Short Day" sequence, the Wizomania choir arrives featuring Kristin Chenoweth (on the left) singing back to back with Idina Menzel. When Kristin hits the high key, Idina suddenly disappears between instant cuts.
Factual error: She's driving down the highway, and her car suddenly and immediately dies, with no opportunity to pull off or park. When she gets out of the car, we see it sitting on the bare forest floor - not even a footpath, much less a road. 14. (00:14:30)
Continuity mistake: When Jack has his temperature taken near the start of the film, the thermometer in his mouth goes from right-side up to upside down, then back to right-side up between cuts.