While visiting MK in July -- Nemo coulo be found "outside" the park at the Ticket and Transportation Center prior to boarding the ferry or monorail to the MK.
We were there in Sept. and Nemo and his seaweed friends were outside of Living Seas. Pictures only, no autographs. Seaweeds were real people, but Nemo was just a big fish! We saw him later on in the day--around 5:00.