The ward number where Dr Helsing is sleeping is "AD 072", a nod to the first modern-day Hammer Dracula film, Dracula A.D. 1972 (1972).
The little dead boy at the cemetery is saying "tittebøh, bloofer lady". "Tittebøh" is Danish for "Peek-a-boo", so the boy is presumably Danish.
The wallpaper in Jack's bedroom has the same pattern as the carpet from The Shining (1980). The color has been changed to blue.
The dead little boy from the cemetery who follows Lucy around. Dave and Lou evolved the concept into a kind of 1970s look. "Initially we thought, it's going to be hard for a kid to put up with all this stuff," said Dave. So instead they approached little person and stunt man Kiran Shah, who they had worked with on many projects. "Boy, can he wear suits. He can work blind. He's just brilliant at doing this sort of stuff, and he's perfectly proportioned. We wanted his eyes to be completely gone, and we wanted to be able to see his teeth and everything. It's a little bit like the 'Jack' puppet from American Werewolf in London, except this is a child." The Elseys also created large dentures and gloves with little bones sticking through the ends of his fingers.
Dracula's long sleep underwater in a box could be a reference to popular vampire series Angel, where this happens to the titular character towards the end of the third season.