Bunny mentions that Jack Frost caused a blizzard on Easter Sunday of 1968, a reference to an actual event.
In one scene, the Tooth Fairy finds a mouse beneath a pillow and identifies it as "one of us, European division." Ratoncito (Little Mouse) Perez, or "The Tooth Mouse", is a children's book character created by Spanish author Luis Coloma in 1894 said to replace lost baby teeth with gifts in Spain, Portugal, France, Italy, and Latin America. In the Spanish dub of the movie, it is even called "Pérez". In Austria it is simply called the "Zahnmauserl" or "Zahnmäuschen" (Tiny Tooth Mouse).
A post-film dedication appears, "For Mary Katherine Joyce. A Guardian fierce and true." This refers to William Joyce's daughter, who died at age 18 from a brain tumor. The movie was based on Joyce's book series "Guardians of Childhood", which was inspired by stories he told his daughter. MK, the main protagonist in Epic (2013), is based on her.
Aside from the Guardians and Pitch, none of the adult characters' faces are clearly seen.
At the beginning of the movie, Jack Frost walks through a Colonial American village. In the background, the folk song village musicians are playing is called "Kempe's Jig." This was a popular early eighteenth century English dance song, named in honor of William Kempe, a famous sixteenth century English comic stage actor, whose work influenced modern comedic acting, stand-up comedy, and improvisational comic skits.