Keith Amos, Rosalind Cash, and John Hancock (the actors who play the family who move in next door to the Keatons) all coincidently died in the late 1990's within about three years of each other.
John Hancock, the actor playing Gus Thompson, died from a heart attack only 3 1/2 years after filming this episode.
When filling Gus & Maya in on their prospective new home, Steven & Elyse tell them that it's the Obeck's house and that they are moving, so the house will be on the market soon. The Obecks were mentioned in season 1's Have Gun, Will Unravel (1982) (specifically Marty Obeck, presumably the father), when the Keatons were discussing whether to have a neighborhood meeting at their home after the burglary. However the Obecks were never pointed out during that episode; all that is discovered here is they live across the street from the Keatons.
When Gus asks Steven if there are any other black families in the neighborhood, he replies that there aren't. However in season 1's Have Gun, Will Unravel (1982) when the Keatons hold a neighborhood meeting at their home, there clearly is a black couple in the background in attendance. So it's not like the Keatons' neighborhood never had black families living there.