I'm not sure about the background music, but I do know that the song at the finale of The Seas with Nemo & Friends is called "Big Blue World," also featured in the upcoming Disney's Animal Kingdom show, "Finding Nemo-The Musical" opening soon.
The new show will have a complete score of new songs for the characters to sing. When Marlin advises his son Nemo to avoid danger, he sings, ?We swim out, we swim back in!? This leads to ?Big Blue World.? Dory sings O?Dory?s Ditty.? Toe-tapping sharks perform ?Fish Are Friends, Not Food.? Nemo sings the plaintive, ?Where?s My Dad?? Dory?s advice in song to Marlin is ?Just Keep Swimming.? And Crush?s nest of turtle dudes sing ?Go With the Flow.?
The new score was written by Tony-winning "Avenue Q" composer Robert Lopez and a capella musical "Along the Way" composer Kristen Anderson-Lopez.
I don't know if there will be a soundtrack album, but I would hope so.
By the way, there is a soundtrack of the Disney Cruise Line Cinderella musical, "Twice Charmed," available on the ships.