Spongebob was at universal. He was in the nickelodean store.
After much googling, I found out that that was sam i am! and the "Nameless skeptic."
you have to keep your eyes open for the photographers at the castle, epcot ball, etc. We didn't find one at the epcot ball, or at the hollywood studios hat, but i'm sure they were there somewheres. There was 6 of them in different locations when we were going towards the castle, and one by like the moat thing on the side of the castle. (you should definetly try to get one here- there was no people in our picture and you see the water and stuff.)
At the character greetings they're right there and take pictures when you give them your card.
We got over 100 photopass pictures, they're generally pretty easy to find.