Yes, I think my neighbor's Olive Downer is actually the Clara O. Downer in the 1880 Census for Ohio. That certainly makes sense. My neighbor's maiden name was Claire Olive Burson, so the names are very similar, and her family frequently uses ancestor's names and initials in naming their children.
I'm having trouble tracing her history beyond this 1880 Census. I thought it should be fairly easy to find Clara Olive Downer's father in the 1850, 1860 , or 1870 Census, but I have not found a perfect match yet. Do you have any of that information?
I have also looked for a marriage date, or certificate for William Downer and Mary J., so I can find her maiden name.