The real Dracula lived during the late 1300s in Romania. He can't be young in the 1970s.
Irwin is actually 1/4 vampire because his dad is 1/2 vampire since Irwin's Grandmama is a human and his grandpa is Dracula.
First time (via flashback) that we see Dracula as a younger man (during the late 1970's) and as a purple vampire bat.
It's revealed in this episode that Dracula is actually Irwin's Grandfather on Irwin's father's side; thusly making (as Mandy correctly identifies,) Irwin a half-vampire and half-mummy.
(After it's revealed that Dracula is Irwin's grandpa)
Billy: So, Irwin is half mummy, half vampire?
Mandy: It would appear so.
Irwin's Grandmama's first name is Tanya.
Irwin's dad stated that Irwin's grandmama told him his father was a navigator on a spice freighter, an allusion to Star Wars character Owen Lars who told his nephew Luke the same thing about his father.
Romeo Must Die:
The episode title segment of Dracula Must Die is a parody/reference to the Jet Li hit movie of Romeo Must Die.