Hardy Har Har, Atom Ant, Squiddly Diddly, Top Cat, Benny the Ball, and Yakky Doodle are voiced by John Stephenson, Don Messick, Daws Butler, and Walker Edmiston here. It was presumed that Mel Blanc, Paul Frees, Howard Morris, Arnold Stang and Jimmy Weldon weren't available to voice them for this TV movie, while Benny's voice actor Maurice Gosfield had died in 1964. In fact with his Daws Butler voice, Top Cat sounded just like Hokey Wolf.
Benny
Maurice Gosfield