I know this posting is quite dated but, I thought I would try a reply anyway. I am researching John Sanderson and Rebecca Grant also. I was just wondering where you had seen that Rebecca had married a Lorenzo Stedman. I see John and Rebecca in New Lisbon in the 1880 census still married. I am also wondering about your date of John's death in the 1870's sometime.
There definetely a connection however. Wondering if you have gotten any further at this point.