William Thomas Farrar, III
I disagree that the genetics favor Leonard being a son of William Farrar IV, at this point of genetics, DNA can not prove a line of descent.
DNA produces unusual results. For instance I am a descendant of William IV yet at Y37 one of the project members, who is a descendant of his brother George is a perfect match.
Without documentation, we can only hope to make educated guesses, deductions. And genealogists use all kinds of documents, truthfully most of them questionable such as deeds to prove lineal descent.
One method used is to follow traditional naming systems. The so called Old Jones System in which the oldest son was named after the fathers father, and oldest daughter after mothers father (same thing for girls), second son would be named for mothers father etc.
Although not iron clad, this technique is helpful in the attempt to sleuth out lines.
In that regard Leonard Farrar named his oldest son John Sutton Farrar. If Leonard was a son of Richard Farrar and Elizabeth Sanders, then John Sutton Farrar would have been a second cousin once removed. Not much of a chance of anyone naming their oldest son after a second cousin once removed.
On the other hand Leonard Farrar did name subsequent sons after the family of William Farrar III, meaning brothers of Richard Farrar, such as Perrin and he even named one son Robert Sanders Farrar, after (perhaps) a brother of Elizabeth Sanders. But that could be because Robert Sanders was personally known to Leonard and had lived with them in Pendleton District, S.C.
One good reason that Leonard Farrar named his sons after kin in the family or Richard Farrar is that Leonard himself was orphaned when quite young, and was taken into the care of Richard Farrar, traveled with that family to Pittsylvania, VA
John Sutton Farrar Jr was grandson of John Farrar and Temprance Browne Widow of Thomas Batte. John was a brother of William Farrar III and an uncle of William Farrar IV.
John Sutton Farrar Jr married Susan Patman, that is known because of some legal documents as regards a lawsuit, and because there is nothing further in the records his existence and prodigy are ignored as if they never existed, as subsequent Farrars, lacking any documentation of their own line, shoe horn themselves into known and documented lines.
Leonard Farrar had a sister who married, according to the pension applicaiton of his brother in law Mashack Stevens.
According to the descendants of Mashack Stevens (Stephens) his wife's name was Milly Farrar, and they married in Goochland County in 1780.
By 1780 Richard Farrar had left Goochland Co, Va where his father William IV and his cousin John Sutton Farrar Sr actually shared property lines, that is lived next to each other in what is now the unincorporated community of Manakin Sabot, and Rochambeau Farms.
With the families of William and John, cousins, living close to each other, it is safe to deduce that in the premature death of one, the other family would, as was the custom in those days, assume the responsibility of guardianship,as the ability of the family provided.
If there were a number of children, then the children would have been split between various families.
Between Perrin Farrar and this person there is a genetic distance of 2 at Y37.
With variations at DYS 460 and CDY/b.
These variations are inconclusive as stands, but do not support a common ancestry to William Farrar IV.