i think along with sony pictures animation and columbia pictures to also help with this film could be Working Title Films, Zuiyo and Nippon Animation

a perfect voicecast should be:
Paul Dano as Popee
Steve Buscemi as Kedamono
Christopher Walken as Papi
Meryl Streep as Mami
Julie Andrews as White Wolf

Danny DeVito as God
Lexi Rabe as Marifa
Will Arnett as Alien
Matthew Broderick as Frog

Kristin Chenoweth as Spider
AnnaSophia Robb as Eepop
Winona Ryder as Onomadek

and i think the composer for the music should be David Newman (Danny Elfman and Marc Shaiman compose the songs the characters sing)