Corrected entry: Mavis knows her parents met in Hawaii because she found her father's souvenir postcard. Mavis is 118, which means her parents met in the 1890's at the latest. There were no postcards like that for Hawaii in the 1890's.
Corrected entry: When everyone is playing "Charades," the Invisible Man shakes his head. The earpieces on his glasses open and close while his head is shaking. This would mean not only is he invisible, he would have no substance.
Correction: It's just a trick of perspective, they don't really open and close. As he turns his head, the angle from which we see the glasses makes it appear as though one arm has been folded in because we don't have any point of reference (such as a face) to show us that the frames have merely rotated.
Corrected entry: When Dracula comes between Johnathon and Mavis after catching them kissing, Mavis' right hand is near her face. In the next shot, her hand is down by her side.
Correction: If you watch closely, she pulls her hand down the moment before the "camera" switches.
Correction: There's no reason to think this. The US was first introduced to postcards in 1873 (although they were invented in 1840) and the first "souvenir" postcards were sold in 1893 (before Mavis was born). By 1898, over 200 companies were selling Hawaii postcards, so obviously there was a market for them and no reason to think local businesses couldn't create said postcard.
Bishop73