I could not really pinpoint specific actors by personality but I definitely was able to place them with charater roles actors have played.

Duke, I would have to say Adam Sandler, loud and abnoxious like in...well pretty much every movie he has done.

Champ, I would have to say Tom Hanks in Forrest Gump, and yes she would definitely be Forrets to a T.

Chopper, I could not think of a person but he reminds me of Chester the Terrier on Looney Tunes.