Kathy and Marian- Amy Blanch is married to one of my Forest Bish, and yes they were cousins. Here is the line of what I have- Lydia C. Updegraff married Amariah Cushman in 1851 Wyandot Co. OH their daughter Alice May Cushman married Thomas Duddleston and had the children you listed..including Amy.
Lydia's sister, Tamzen Updegraff had daughter Harriet Nye who married Francis (Frank) Bish. Forest is their son. I wish I had more, but I was wondering if anyone had anything on what happened to AMy and her children??