When Florida was explaining the sleeping arrangements to J.J., you can see J.J mouthing the same words while Florida explaining the sleep arrangements.
When Florida tells Willona she'll be back and rushes out the door to bring Grandpa and his girlfriend back from the bus station, she exits to the right toward Willona's apartment instead of left toward the elevator.
The first time there is a knock on the door, J.J. runs to answer it, thinking its going to be his grandpa. As he crosses the set, you can hear Jimmie Walker say "Sh*t finally!".