Well, we have uncovered a relative. I won't name him, to preserve his privacy, except to call him B. His grandmother, Mary Theresa Ortmann, was the second oldest sister of our great-grandfather, William John. He has posted a picture of her, which I'll include here:
I don't have a picture of Great-grandpa when he was young, unfortunately, but I'll try to find one of him so we can put them side-by-side and see if they look alike.
I'm excited to have made this connection. Although I have no intention of showing up his doorstep, I'm happy to know that B. exists and to have this picture. I'm very touched by the whole thing.
See you soon --