The only actor to appear in all three films and the short-lived cartoon series was Gilbert Gottfried. Jack Warden appeared in all three films, but not the cartoon.
In the cartoon series, Ben Healy is a police officer, which wasn't his profession in the films.
To avoid copyright infringments or paying royalties every episode, the studios told the band creating the theme song to make it sound absolutely nothing that even resembles George Thorogoods Bad to the Bone or Problem Child by AC/DC.
In the film Problem Child 2, Murph was a bully to Junior, but in the cartoon they're friends.
The cartoon takes place live in Toe Valley, not in Mortville or Cold River from the films.