Oma Eugene Bechtel married my grand aunt, Flora Mae Reeves, dauther of Josiah and Lydia Reeves. My grandmother was her sister, Leola Eugenia Reeves, my mother was Leola's oldest daughter, Norene Jackson.
I read your post and wasn't aware of Oscar B. Oscar was not listed in the Illiopolis, Sangamon, Illinois census in 1880.
Was Oma married to a Alice Huff at any time? Since Oma and Flora weren't married until 1941, it is probably safe to say he was previously married. I found Oma and Alice with 2 daughters, Alta and Jeanette. If that is the same Oma I was searching for. I remember my mother mentioning the name Bechtel.