For a quick sequence where we see a close up of Bugs' hands massaging Elmer's scalp to the notes of a short piano solo in the opera, they are deliberately drawn with five fingers for the sequence so they can believably follow the tune.
Was originally pitched as a Bugs Bunny/Elmer Fudd pairing set in a barber shop, with no singing, but it was decided it would be funnier if it was a spoof of the classic opera "The Barber of Seville".
A signboard lists the opera's featured cast as Eduardo Selzeri, Michele Maltese and Carlo Jonzi, references to Edward Selzer, Michael Maltese and Chuck Jones, their names appear in Italian dialect, and are then transferred to English.
In author Jerry Beck's 1994 poll of animators, film historians and directors, "Rabbit of Seville" was ranked #12 among the 50 greatest short cartoons of all time.
The outdoor theater resembles the Los Angeles Greek Theatre, set in a more rural area than its more storied cousin, the Hollywood Bowl. The subtle sounds of frogs croaking would seem to confirm this. It opened in 1939 and is still going strong in 2022.