Maurice LaMarche learned to imitate Ray Liotta not by watching his films but by coincidentally having dinner in the same restaurant as the Goodfellas (1990) actor and listening to him speak throughout the evening.
Michelangelo is clearly an imitation of actor Kirk Douglas, father of actor Michael Douglas.
"Hooked on a Ceiling" is a pun on the song "Hooked on a Feeling," originally recorded by B.J. Thomas in 1968 and later covered by many artists, most famously Blue Swede.