In addition to "Prima Donna," Phantom has other contrapuntal pieces. The song in the cemetery has two or three melodies, depending on whether Raoul joins in early (as in the West End) or later in the song (as on Broadway, except since Norm Lewis has been playing the Phantom.) Additionally, the final lair scene has a contrapuntal section, where Raoul is asking for Christine's forgiveness (for what reason, I've never figured out -- maybe for failing to rescue her) and Christine is singing that the Phantom is her false friend and fallen idol. Since my brain is currently fried, I can't remember whether the Phantom is singing at the same time -- I think he is.
Audrey
Audrey, the Phantom Phanatic, who nonetheless would rather be Jean Valjean, who knew how to make lemonade out of lemons.