Re Count von Verminhaven's name: "von" is German for "from"; "vermin" are animal pests such as rats and lice; and "haven" is a safe port or harbor. So he is the Count from a safe harbor for rats.
Widow Twankey's musical number has a melody in the style of a Parisian nightclub in the early 20th century, while the male dancers behind her "Walk like an Egyptian" as in The Bangles: Walk Like an Egyptian (1986) recorded by The Bangles in 1986.
At 21:24 Widow Twankey floats to the ground holding a parasol as a parachute; emulating a classic scene from Mary Poppins (1964).
Widow Twankey's sexual innuendos and clichés rival those spoken by Nebula.