The families you mention were very good friends, and may even be connected back in NC.
John and Byrd's sister was Harriet M. Grace, the second wife of James Bennett. James's first wife was Elizabeth Chambers, whose brother, John Chambers, was married to Elizabeth "Lizzie" Gilmore. Lizzie's sister, Jane Gilmore, was married to Thomas Jefferson Farmer.
Parents of Harriet, Byrd, and John were James Grace and Lucy Mobley who married in Tattnall Co GA. The Grace family was from Edgecomb Co NC, and the Mobleys were from Duplin Co NC. The Bennetts were from Bertie, Martin, and Beaufort Co NC. The Chambers were from Abbeville Co NC.