When Boris is bathing in the huge puddle before Stella comes along, the language he is singing in is not actually Russian. Boris' voice actor, Charles Fleischer, was asked to sing something that sounded Russian.
During the E.D.A.S. sequence, a Kaltag look-alike and a Nikki look-alike can be seen in two open windows of the hotel, and a Balto look-alike can be seen on the roof of John's Bar next door. Additionally, the terrier from Balto: Wolf Quest (2002) can be seen. Furthermore, the dog with the twitching eye, and the Saint Bernard-like dog from Balto (1995) can also be seen.
In the film's original script, Kodi does not help rescue Balto. Phil Weinstein pitched the idea of Steele being the one who volunteers to go help Balto on the rescue since, in the original draft, Kodi wouldn't go. Phil thought it would be interesting for Balto and Steele to be out alone together. The E.D.A.S. dog alert sequence was added, and the flashbacks to Kodi as a puppy were added in Jenna's song "You Don't Have to Be a Hero". The opening song visuals originally told more of the story of Kodi, getting promoted from the dog in the back to the front. Also, the opening scene began with a postman addressing a letter, we follow the letter as it gets sorted, then bagged in a sack, then placed on a sled to get delivered. There are some elements of this in the final version. The close-up of the letter stamped "AIR MAIL" at the end of the movie was just a pay-off for what was set up in the beginning. The ice bridge sequence was also added.
The Balto look-alike can be seen multiple times in the movie: during the E.D.A.S. sequence, to Kirby's right when he, Kodi, and Ralph are looking at Duke's plane, and when Jenna sees Kodi with the other dogs. The look-alike can also be seen as part of Kodi's dog team multiple times throughout the movie.