I am deeply familiar with the Harrell family above. Yes, Thomas Harrell's daughter Barbara (b ~1740) married Jonathan Cain, a Quaker, who was born 1 Jan 1729/30 (some say in England; I suspect in Chowan or Bertie NC) and died 30 Nov 1784 in Union County, South Carolina. He was a son of John Cain and Sarah Hodges. Jonathan Cain and Barbara Harrell had 12 children; they named their eldest son John. John Cain was b 22 Jun 1760 in Edgecombe or Halifax Co NC, d 1 Apr 1838 in Wayne County, Indiana.
Unfortunately, a Cain researcher several decades ago erroneously leaped to the conclusion that Barbara Harrell's mother Rebecca was a Cain. There is not a shred of evidence for this, anywhere. Rebecca was a daughter of Robert Evans and Ann Hooker of Chowan and northern Bertie NC. She was named as daughter Rebecca Harrell in Robert Evans' will (he died at Wiccacon in Bertie in 1745); Thomas Harrell was the first purchaser at the Robert Evans estate sale. Rebecca Evans and Thomas Harrell definitely married before 1743, as proved by a deed of sale on the Roanoke in Bertie. When they moved from Bertie NC to Edgecombe NC in 1759, it was to the neighborhood of her maternal relatives. Her second husband John Skinner had been an adjoining neighbor of Thomas Harrell's first cousin(also named Thomas Harrell) in Chowan (now Gates) NC. Rebecca Evans Harrell Skinner was still alive in 1775, but after that I lose track of her. Her son-in-law/stepson Charles Skinner, who married Elva Harrell, daughter of Thomas Harrell and Rebecca, died in Spartanburg SC in 1825.