From being God in both of the movies, Bruce and Evan Almighty, I think Morgan Freeman would be the right Blue Caterpillar. With his background experience with such wise characters, Morgan Freeman would totally deliver the role phenomenally.
Tom Hanks -One of the most talented Actors of our generation. Truth is, I forget about all of his movies as each character he portrays become an individual of their own. Tom Hanks disappears when he steps on the screen.