The parts of Lewis and Wilbur had to be recast when the original actors' voices broke.
After reading the screenplay, director Stephen J. Anderson actively lobbied to direct this movie. As an adopted child himself, Anderson personally felt many of the emotions (questions about belonging, being wanted, etc.) that Lewis shares in the film. [source: director's DVD commentary]
The character of Lewis was voiced by both Daniel Hansen and Jordan Fry. Daniel Hansen voiced Lewis at the beginning of the film's production, and when Lewis needed things changed, they had Jordan Fry re-dub some segments. It is noticeable in some parts of the movie.
Walt Disney Feature Animation wanted to assert themselves as being separate from Pixar Animation Studios renaming themselves Walt Disney Animation Studios. This is the first film to show the new Walt Disney Animation Studios animated logo, which incorporates several seconds from El botero Willie (1928), the first Mickey Mouse cartoon to feature sound.