early 1920’s. The tennis court doesn’t look like that anymore (which is fine, none of us play tennis). For the plumber, note the spigot there in the lower right, now which mystery pipe do you suppose That is?
The only positively identified individuals are the three closest: George Creevey in the rocker with the most impressive pipe, William Webster Ellsworth with the white moustache, and Eileen Creevey closest to the camera on the bank (shorts and glasses), the boy looking at the camera might be Kennedy Creevey, but he could easily be the boy looking away too.
I should add, that according to the series, the people playing tennis also dressed in the same fashion, actually one has a tie and a hat on…