Character mistake: When Dracula puts Johnny on a time-out, it is shown that Dracula has the ability of psychokinesis. Yet during the scene when Mavis visits the human village, when one of the dressed up zombies loses its head, Dracula jumps into the scene to physically put the head back to its body, further risking being spotted by Mavis, which he wanted to avoid. (00:16:15)
Suggested correction: Using this power would also be a risk of Mavis finding out because his magic has blue effects around which she would spot.
I doubt that, she was facing the opposite direction of the headless zombie the entire time, and the zombie didn't stand too close to her. However, I have realised that the magic does seem to make sound, and the headless zombie did stand close enough to Mavis for her to would have heard Dracula's magic if he were to have used it.
Even with the sound, I doubt she would have noticed when there are what looks like villagers approaching her with pitchforks and torches.
Factual error: Johnny shows Mavis the sunrise by keeping her back in the shadows. But if your whole body is in an object's shadow then you can't see the light source. The rising sun is reflected dead center in Mavis' eyes, which means the sunlight is touching her, which means she ought to be on fire.
Suggested correction: Not really though. You see you can stand in the shadows but still look at the sun. No one actually does but it is possible.
A shadow is caused by something blocking the sun. If you stand in the shadow (i.e. you are no longer casting your own shadow), you can not see the sun. Think of lying on the beach and someone stands over you in such a way their shadow is cast over your head. The sun would be blocked from your view. You obviously would still see all the scattered light, but the sun would not be reflected off your eyes.
Continuity mistake: When Dracula and his architect are going through blueprints of the hotel, Dracula is seen with a coffee in his hand. Mavis spits from the ceiling and it drops down to the table where the blueprints are. When they scan up to Mavis he has coffee, when they scan back to Dracula and his architect there is no coffee in his hand.
Continuity mistake: When Dracula is heading towards Mavis' room, one of the rooms he walks past is Room 174. When he finally reaches Mavis room, her room number is also 174.
Factual error: The airliner keeps its undercarriage down far too long. Normally the wheels would be retracted while the aircraft was still over the airport - this one is almost at its cruising altitude before they do that.
Continuity mistake: When everybody is playing bingo, the word bingo is placed correctly on the cards but none of the bingo numbers are in the right place. Plus, when the bingo lady calls out the numbers, everybody is stamping the number that was called under a different letter. Ex. When the bingo caller calls out N-27, Eunice stamps the number 27 but the number where she stamps it is under the letter I.
Plot hole: Frankie makes reference to fear of fire early in the movie in the scene with all the guests arriving at the hotel. And in the scene in the local village with the monster festival, a single match is used to send him on a rampage. But throughout scenes in the hotel itself, there are lit candles, candelabras and torches throughout, most noticeably in Mavis' room during the scene where her monster friends (Frankie included) are addressing her idea of going to a human village. None of this fire affects Frankie at all.
Suggested correction: Candles are a controlled fire, and small in a room that's mostly made of stone. The match at the town was a sudden fire in front of his face that startled him. Even if he was concerned by the candles in the past, I'm sure that in the 115 years since the hotel opened, he was OK with it.
Continuity mistake: The length of the corridors and passages inside the hotel are much longer than the outside of the hotel itself.
