Animation Source Forums

Even if it were "official" there'd still be no answers to questions like that. Even the producers of Balto and TLK and almost every other animated movie never created official parents, grand parents or whatever of the main characters unless they were part of the story, most like to leave it to the fans to create fan-characters or never even thought about it.
You coukd spend hours e-mailing Disney or Universal or Dreamworks asking about characters like that and get no answer.

Why not just make it all up? Ahh, the joy of fandom.