Krankheit (the last name of the pharmacist Felix works for) is German for "sickness".
The dialog at the very end of this movie is a take-off on the final scene of Some Like It Hot.
The gypsy costume of the werewolf is a reference to "The Wolf Man", in which the werewolf who bit Larry Talbot (Lon Chaney Jr.) was a gypsy (played by Bela Lugosi).
The heads of the "Boris" and "Monster" figures are the same basic shape, appropriately enough, with Boris's fine-tuned for a more human appearance and the Monster's for that monsterish look (look at the figures' heads when they're in the same shot, both more or less in profile, during the "greeting the guests" scene!)