Wikipedia tells me (because I sure as hell couldn’t remember) that Happy Feet ends with the Penguins convincing the world via dancing to stop overfishing Antarctic waters, which is celebrated with dancing. Then Prince happens. I’m not sure what narrative path a sequel to the musical would take, but the original had one of the highest grosses of 2006 so I’m sure they can render out a few more dickheaded old penguins to teach rhythmic life lessons.
Several of the principle players- namely Elijah Wood, Robin Williams, and director George Miller- are already signed to return to their various roles and positions. One would presume some or all of the other original cast members such as Hugh Jackman, Nicole Kidman, Brittany Murphy, and Hugo Weaving are more than likely to reprise their roles too.
I hope to hear the announcement of James Gandolfini voicing Whale any day now.