The Other Darrin: A few characters were recast during the course of the series and specials. In particular Melissa had four different voice actresses.
Talking to Himself: Len Carlson voiced Bert and two of the pigs, as well as numerous ancillary and minor characters. In "The Phantom of Sneer Mansion!" and (arguably) "Black Belt Bentley!", Bert's voice is mistaken for another voice performed by Carlson. Other cast members also voiced multiple characters.