Paul McEvoy Director, Producer Mindy Cohn Velma Dinkley Voice Grey DeLisle Daphne Blake Voice Frank Welker Scooby-Doo , Fred Jones Voice Matthew Lillard Shaggy Rogers Voice Diedrich Bader H.A.M. Voice Eric Bauza Clark Sporkman Voice Jeff Bennett Colt Steelcase Voice Mark Hamill Zip Elvin Voice Malcolm McDowell Sly Baron Voice Mark Banker Screenwriter Sam Register Executive Producer