Hi Shelly,
No, I don't have any death records for Sam or Lavina. I can only estimate, by census records, that Sam died after the 1875 NY state census which was done in June of that year. It's the last census he appeared in. At that time, he was living with his niece and her family in Farmerville, NY listed as a widower; Lavina last appeared with Samuel living in Johnstown, Fulton, NY in the federal census of July 1870 so she certainly died between 1870 to 1875.
Now, for the children: there were five, that I'm aware of. Sarah, I have next to nothing on, other than being born around 1830, so I hit a dead end with her; sons, David and George, both married and had families, and both died in 1864 fighting in the Civil War; daughter, Elizabeth, died in Johnstown, NY in 1918 - she was the widow of Charles Foster at the time of her death. Maybe her death certificate might have her mother's maiden name? I know my great-grandfather, Charles, only had her first name recorded, which was disappointing, to say the least.