I found it unrealistic that Chip told Barbara that he and Ernie didn't remember THEIR mother much...Remember, Ernie was Chip's friend, Sudsy, and was adopted after the real older brother, Mike, moved away. When Steve told Barbara's mother that he had THREE sons, that was simply not true. Did Mike suddenly not exist? Steve has FOUR sons....Mike, Robbie, Chip and (renamed) Ernie. Amazing how these sitcoms re-wrote their own history.
I agree that Dawn Lyn was an awful choice to portray Barbara's daughter. Awful haircut, yes, too short dresses where he panties are in plain view, not photogenic or cute in any way. Back in the 60s, when the show was new, I watched it then and thought the same thing. She was annoying to me.