The Other Darrin: This special’s the first time both Ross Bagdasarian Jr. and Janice Karman took over the vocal roles of Dave Seville and the Chipmunksnote Ross Bagdasarian Jr. voicing Alvin and Simon with Janice Karman voicing Theodore and would be throughout the franchise until the live action/CGI movies with Jason Lee. note Though Ross still provides Alvin's singing voice, Janice does Theodore and the Chipettes' singing voice and Steve Vining for Simon
Real-Life Relative: Husband and wife Ross Bagdasarian Jr. and Janice Karman picked up the franchise. Then later on, their kids Vanessa and Michael started helping them.
What Could Have Been: Production of the movie became too time consuming, and with the deadline for the completed project fast approaching, several scenes in the original script had to be re-written to make them simpler for the animators to animate (including the sacrificing scene), or cut from the script completely, thus resulting in a much shorter movie with fewer locations The Chipmunks and Chipettes actually visit.
Early concept art also reveals that the producers originally intended to have a scene where the boys drop off a doll in a church confessional and that the sacrifice scene was originally set on top of a Mayan pyramid instead of a crocodile pit. Another sketch shows the boys in some sort of sewer or prison with two men prying open bars at an opening at the top.
Money, Dear Boy: David Cross makes it especially clear that he's in the movies for the money, noting that being in the first paid for a new house (he seems to have had enough with Chipwrecked though, which he called "literally, without question, the most unpleasant experience I’ve ever had in my professional life").
The Other Darrin: Initially, Ross Bagdasarian Jr. and Janice Karman portrayed Alvin, Simon and Theodore in the film, but were replaced at the studio's insistence with younger actors Justin Long, Matthew Gray Gubler and Jesse McCartney respectively.
It’s not the first time Steve Vining provided the singing voice for Simon.
What Could Have Been: Ross Bagdasarian Jr. was originally set to portray David Seville; however, due to his age (58 at the time of filming), the younger Jason Lee was chosen.
Both he and Janice recorded their lines for the Chipmunks but were replaced by younger actors for promotional reasons.
Word Of God: According to Ross Bagdasarian Jr. (and Zachary Levi) the piano seen in the movie is the actual piano Ross Bagdasarian Sr. used to write and perform “The Chipmunk Song” as well as “The Witch Doctor” that launched the Chipmunks franchise.
Dave's house number is 1958, the year Ross Bagdasarian created the Chipmunks and released "Witch Doctor" and the "Chipmunk Song."
Creator Backlash: Actor David Cross has said that the third film was the most unpleasant experience he's had in his life as a professional.
Franchise Killer: It seems the unanimously negative reviews of this movie, combined with David Cross publicly speaking about his negative experience on the film and the lower box office total compared to the first two, has finally brought this wretched franchise to it's end. No news of a fourth film has appeared yet and seems like it never will.