Well, it's not Rick.
And it's not Caleb.
But maybe this page from DC Comics Cartoon Network Action Pack #34 can start you off with the right letter. You'll need to look at the issues after this one to figure out the rest. Although I don't think we ever got to hide the last letter. I can't remember if we finished the scavenger hunt.
For those of you who don't care what his name is... please enjoy the sooper powered inking on this page by Rob 'The Iguana' Smith, penciled by Mr. Maurice Fontenot, of course.