OK, so how did the book Martha wrote survive both the fire and 118 years of existence? (No acid-free paper back then.) Both are answered simply that it was locked in a safe. Martha locked it away, intending to open the safe and retrieve the book from the airtight safe when Mavis reached her 118th birthday. After the fire, Dracula went back to see if there was anything salvageable and found the safe with the book inside. Either vampires have a magic that allows them to unlock things or he just knew the combination.
Dracula's Control Freak tendencies make sense when you consider the fact that one of the traits of a classical vampire is OCD (specifically, one of the ways to deter a vampire was to scatter rice/poppy seeds, and the vampire would be compelled to count them before it could move on).
Dracula singing "Grow Old with Me" seems like a strange Adam Sandler Shout-Out , but it makes sense when one realizes that he is accepting Johnny despite the fact that his is human, and will eventually grow old.
"You only zing once!" Is the reason why Dracula finally goes after Johnny. Fridge Horror kicks in when you realise that since he already zinged, and presumably lives forever, he's doomed to a literal eternity of loneliness. Explains a lot about both his hatred of humans and his rabid protectiveness of Mavis.
On that note, it is basically implied at two or three points through out the film that Johnny is going to become a vampire in order to stay with Mavis, this may be a case of getting crap past the radar....
One related to the game on the Nintendo 3DS: Why the hell are the hotel staff and monsters attacking Mavis? Worse yet, this can even happen in plain sight of her own father and friends, and none of them would lift a finger to help you.