Sorry to disapoint you, but I don't think there is going to be another Balto movie. Also, no one knows how Aleu is doing, thats up to fanfiction.

Well, no one really knows what happened to Aleu after the second film, and no one even mentions her in the third. So all we know is that Aleu led the pack across the great water. You can make a fanfiction, telling people what you think happened after that, or you can read other fanfictions about it. That's the best answer I can give.