I'm not sure of the relationship but i do know the men in the photos dated 1907 appear to be the same age. Those two photos look like old Grad. photos from school.
Also the two Jesse Seaver photos appear to be the same man . The oldest of the Seaver photos is the Rosa Seaver photo i'd date it about 1880-1900. I'm guessing she is an older sibling or possible mother.

These photos were found with the Seaver photos:
Frank Giltner
Charlie Foster who married Annie Kelley
Henry Straughn
Susan Montgomery-Straughn

I'm guessing they all belong together but i'm not sure.

Hope this helps!
Don Howell