Your last sentence "speaks volumes"! Thus you may need to seek help in Franklin County, TN? My initial scan uncovered three marriages for Edward Dodson Swann: Martha McKeel (7 Sep 1849), Malissa or Matilda Covey (25 Apr 1854), and Margaret Wilhite (20 Sep 1870). Reasonably certain your grandfather's sire found 1880 TN-Franklin-District 9-093-Image 6 at age 19? Notice his younger brother, Rufus. Wonder if he's the same person that settled in Wood County, TX? That'll explain his absence for 1870 Franklin, TN Census. Also note younger brother, Horace, age five. Online death certificate (14 Oct 1875 - 3 Jun 1964) in Lamar County, TX. Many surname Swann(s) in Franklin, TN with the eldest enumerated as Edward age 80 and born in Maryland per 1850 TN-Franklin-District 9-Image 5. Keep searching. Highly possible you might find a Sons of the American Revolution database to add to your ancestry?