Partial bio on William Steel: "Born in Biggar, Scotland, on August 26, 1809, and emigrated to the United States with his parents in 1817. The family first settled near Winchester, Virginia, but soon moved to Monroe County, Ohio. From 1830 until the Civil War, Steel was a leader in the “Underground Railroad” in SE Ohio".
So there's another Virginia connection. Perhaps John Gibson, Esq emigrated around the same time as the Steel family, and initially settled in Virginia, as well. That would tie in with Josiah's birth in VA, as per those census records. Mary's birthplace might be VA, too.
Before 1853, systematic statewide recording of births, marriages, and deaths did not occur in Virginia. Many pre-1853 marriage records survive, but birth and death records are rare.
If this is the Gibson family Dalek is researching they're quite interesting, particularly with the abolitionist connection.