Yes, sorry, John Hewitt died in Spartanburgh in 1812. He had a son named Alexander. Alexander is found there in the 1820 census with apparently a wife and a young female child.
Alexander Hewatt is found in Gwinnett Co., Georgia c.1830. He was born 1797 and died 1857. His wife is Mary(?Lancaster?), born 1800 and died October 21, 1883. Children are:
Eunice Hewatt, born August 10, 1818 in SC/ died January 18, 1877 in Gwinnett County/ married August 22, 1844 in Gwinnett to John Arch Austin.
William M. Hewatt, born 1822 in SC/ died UNKNOWN/ married in Gwinnett April 21, 1840 to Elizabeth Jane Weed.
Lucy Hewatt, born October 15, 1823 in GA/ died January 11. 1906 in Gwinnett Co./Never married
Joseph Benjamin Hewatt, born June 1829 in GA/ died August 4, 1883 in Gwinnett Co./ married in Gwinnett 1851 to Lucretia Austin(sister to John Arch Austin).
Alexander Abner Hewatt, born January 2, 1834 in GA/ died April 25, 1921 in Gwinnett Co./ married in Gwinnett June 1, 1857 to Martha Lemons Brannon.
Everyone except William Hewatt is burried at Friendship Primitive Baptist Church in Lilburn, Gwinnett Co., GA. Joseph Benjamin's son Joseph Crancel Hewatt(my grandmother's grandfather) was a preacher there for many years. The church was founded and organized in 1833. The first preacher was Kinchen Rambo.
I don't know when or why the spelling of Hewitt changed to Hewatt, but all the Gwinnett branch uses the spelling HEWATT. When you research it in census though beware, it can be spelled Huat, Hughat, Herratt, Hiatt, etc.. just about anything that starts with "H". There are a couple of good books in Gwinnett County that document the family, The History of Gwinnett County, by J.C. Flanigan and Families of Gwinnett County. Both are available at the Gwinnett County Historical Society in Lawrenceville. None state that Alexander is a son of John in Spartanburgh, just that he was from South Carolina. Given the scarcity of the name and the 1820 census finding, along with John's will, I think it's a safe bet that they are the same Alexander.
I am still looking for a marriage record for Alexander and Mary.