As for interacting with friends, there's been a video online of a grandfather and granddaughter have a dance competition, separated by a street. They stand across the street from each other, taking turns dancing. Social distance is kept, and they get to do something together. Maybe something like that could be planned. If not across the street, across the yard? Pick an activity they would like.
I had a boss once who had a video projector and she would show a movie outside in her yard on a large sheet she had hung up. Maybe have only one or two guest and have them bring their own snack and drink? Lawn chairs could be spaced far apart.