The joke with the elephant defecating while Edward daydreams was unscripted. The filming crew found it hilarious, and quickly zoomed out to get the whole thing.
Matthew McGrory (Karl the Giant) appreciated the shoes the costume department made for him out of luggage. While he was alive he held the Guinness World Record for the largest feet: size US 29.5. He also held the record of world's tallest actor, standing at 7'6" (2.29m).
Ewan McGregor was cast as Young Ed Bloom when producers noticed the striking similarity between him and pictures of a young Albert Finney, who plays Senior Ed Bloom.
Though the circus Colossus (George McArthur) is shown being dwarfed by Karl the Giant (Matthew McGrory), in reality he's only three inches shorter. McArthur is 7' 3" and McGrory was 7' 6". Creative camera angles and platforms were used to exaggerate McGrory's height.
Even though Young Edward lands in Korea, the ventriloquist and his puppet speak in Tagalog (language of the Philippines) while the Siamese twins and Edward speak in Cantonese (a Chinese dialect). The soldiers who pull the ventriloquist off the stage speak Mandarin Chinese (language of mainland China and Taiwan) while the other soldiers speak in Korean.
Johnny Depp: Uncredited, as the voice of the catfish the younger Edward Bloom caught with his wedding ring the day Will Bloom was born. Frequent Tim Burton collaborator Depp was unavailable for the film due to his commitment to Pirates of the Caribbean: The Curse of the Black Pearl (2003). However, Depp was able to stop by the studio during post-production to make this voice cameo.
Tim Burton: one of the clowns sitting close to Mr. Calloway's trailer, who flees when the wolf jumps from it.
Tim Burton: [distorted female face] Edward imagines Jenny becoming the Witch, with her face aged and wrinkled and one eye missing.
Tim Burton: [black and white stripes] in the circus scene, the stripes can be seen on the ringmaster's pants and also on the outside of the giant's box.
Tim Burton: [The Wizard of Oz (1939)] The trees move and trap young Edward just like the ones that argued with Dorothy and the Scarecrow.
Tim Burton: [Stanley Kubrick] Twin girls in the circus scene resemble the Grady sisters from The Shining (1980).