Narrative
Standing from the left:
Mary (Brooks) Stuver, wife of Jacob
Mary Bender, unmarried sister of John Bender
John Bender, former brother-in-law of Jacob
-> (John's first wife was Jacob's younger sister, Adeline)
Trella (Gunn) Null, great-niece of Jacob
Mabel Bender, John's second wife
William F. Stuver, nephew of Jacob
Seated is Jacob Stuver Jr.
The print's upper-right-corner artifact (which I believe to be a partial lens flare) is unfortunately placed, as it obscures William's face quite thoroughly. So far, it is the only photo I have of William other than a few in his infancy and childhood, so I don't have any good representation of him as an adult.
The date of the photo is unknown, but Mary's death occurred in 1930, and Jacob's in 1933, so I suspect this is from sometime in the late 1920s. It must be after 1925, as John Bender is pictured with his second wife Mabel (whom he married sometime the death of Adeline, his first wife, in 1925).