Real World References
Firebird was an automobile released by Pontiac between 1967 and 2002.
The Firebird appears in real world Russian folk tales where it is often the object of a difficult quest, fitting in with Ceasar Borgata's difficult quest to take back the city of Chocula from Carpool. The same mythical bird is also the subject of a Stravinsky ballet.
Being 'birds' they fit the theme of Transylvito units being slang terms for women (along with Goyles, Dolls, and Molls.)