I have seen no documentation that this John Frazier is the son of Joseph Frazier. The Estep narrative did not name the father, although he did name the Frazier brothers and the relationship to the Scott family in early Augusta Co, Va.
I have seen Ewing history which says John, 1735, is either a brother or son of Joseph Frazier, son of Joseph Frazier who married Eleanor Ewing.
Where is the documentation that John Frazier, born about 1717, is the son of Joseph Frazier?
I see no documentation that John Frazier died in Augusta Co Va. Family lore is he left VA, and the Chalkey's Ledgerwood entry does seem to establish that. It says he left the state, and died in an accident.
From Revolutionary War Pension Records, there was a John Frazier, born 1755 at Calf Pasture and Christian Creek area of Augusta Co, lived in Rockbridge Co in 1832, served in the Revolutionary War under Lieutenant Campbell and others. You do not show him in any of your work, thus it is in error. He is a documented John Frazier, and likely the son of the John Frazier who you (erronously, I believe) state died in Augusta Co, and was first married to Isabella Moody. Isabella was listed as a widow in the late 1750's, but that title was conferred on women who husbands had left them, in additon to those whose husbands were deceased.