Are you sure Thompson was born in Macon N.C. rather than Towns or Union Ga?I don't have any trouble with him going back there to be married, except it looks like he took the minister(Joseph Burch)with him.
I can't tell you who Robert's parents (Thompson's GPs) were since I'm not really an Allen researcher, but it looks like they are William and Nancy Allen, who appear to have moved to Rabun Co. (out of Macon N.C. or possibly Pendleton dist S.C.) then to Gilmer Co.
By the way, in his will, posted in Town's County records in June 1856, Jarratt Burch left thompson and his seven siblings (Jarrett's grandchildren) $8.00 each.As you know, the younger children went to live with their grandparent's Jarrett and Milly Pinson Burch in Union Co.Their older brother, Jarrett Erslie Allen was made their guardian and applied to sell his father, Robert's, bounty land.Jarrett Erslie Allen himself died intestate pre Feb 1858 and left widow Lucretia McNabb Allen (she a daughter of Taylor McNabb of Union Co. Ga.) with children Emily Jane, James T., Mary Ann and Kansas E. Allen.
Another of Thompson's siblings, Joseph P. Allen was named for his maternal great grandfather, the Rev. War soldier Joseph Pinson.There is a mountain known as Pinson Mtn. (now shown on maps as Penson Knob) in Rabun co. where Joseph and clan (incl. Burch's) pioneered the Wolffork Valley c. 1821.
Anything you can tell me to fill in the holes in my info. would be appreciated.