Sally, I wasn't sure if the last name was Jones or Loner due to the handwriting.You may find the boy Jefferson Jones/Loner??? in a later census to confirm the last name.
George's second wife was a widow in 1880. She was Mrs. Elizabeth M. Duncan. I do not know what her maiden name was. Her maiden name was probably Freeman, as you cited from the death certificate.
I do not know what her middle name was. I was in error when I referred to her as Margaret. Sorry. She is probably the Martha you noted.
The 1880 census shows Dora, Cora and Saphronia were Duncans so I believe they were her daughters. I think the census taker just simply left the relationship column blank. Additionally, in 1900 census she says she has had 3 children.
Mrs. Tildon Smith must be a child of either Dora or Cora, since Saphronia died a Duncan(unmarried).