The overall concept is a mishmash of Toy Story (1995)/Toy Story 2 (1999) and Small Soldiers (1998). Spaceman Swinton is based Buzz Lightyear from Toy Story.
A large cardboard cutout resembles Superman, another Warner Brothers/DC Comics character, whom Scooby-Doo has occasionally met in crossovers.
Walter Claphammer appears to be based on Barney Fife from The Andy Griffith Show (1960). Barney's actor Don Knotts starred in Guess Who's Knott Coming to Dinner? (1972) and The Spooky Fog of Juneberry (1972).