The final frames, of Daffy on the giant's watch face, is likely a cheeky wink at rival studio Disney's ubiquitous Mickey Mouse watch.
Daffy and Bugs acknowledge the original fairy tale as each breaks the fourth wall.
Bugs' mailbox lists him as 'B. Bunny, Esq.'. In the U.S.A., the title 'Esquire' is usually associated with lawyers.
Giant Elmer is reading 'Little Men' - a play on the fact that he is a giant. Even so, it must be noted that Louisa May Alcott wrote a sequel to 'Little Women' called 'Little Men'.
Daffy makes reference to the workings of the entertainment industry several times.