I believe, after a bit more research, that James Stewart's father was probably John Stewart b: 1690, Dunblane, Perthshire, Scotland d: abt 1782, Rockbridge, Augusta County, Virginia m. Mary Shaw b: 1698.
I can't totally prove it yet. I have also found this reference:
Register of Maryland's Heraldic Families Vol 1
John Stuart settled on "Borden's tract", 1752; he was one of the signers to the "call" to the Rev. John Brown, as minister of Timber Ridge and New Providence, in 1752. In 1757 he buys a lot in Staunton, at the s.w. cor. of Beverly and Augusta Streets. Records show that he was associated with David and Archibald Stuart in business. He m--Sarah Given--Section now Rockbridge Co.--1.--dau--of
Samuel Given, one of the ch early justices of Augusta-later resided in Bath Co.
John Stuart, Jr. (b-- ??, d--1771), lived on Middle River of Shenandoah, m--Mary(probably Mary Steele);
William Stuart (b--??, d--1768), lived on the upper
Cowpasture, m--Margaret Usher;
James Stuart, lived on Stuart's Creek, br. of the Cowpasture River, was a victim of the Indians, 1757--m--Ann ............;
Jane,left "father's town lot" by bro. William in his will--she m--William Marshall(no other records);
Rebecca (name sometimes given as Becky, which led to idea
name was Eliz.), m--Ralph Laverty, business partner of her bro. James and early settler on Cowpasture River.
1. John Stuart (Stewart) (b--1727?, d--1771) will made April 4, 1771, admn. of estate granted to Wm. Hamilton, March 17, 1778, m--Mary (prob. Mary Steel)--lived
on "Middle River of Shanandoe".
Ch: Jane, under twenty-five when will was made, so stated in will;
Mary, under 18 when will was made, m--John Smith; 2--m--Mills;
Elizabeth, under 18 when will was made, m--Samuel Lessley;
William, oldest son, "plantation devised him by his uncle William";
John, not yet 20 when will was made (b--??, d--1790), m-Frances Burnside, dau--of John and Martha Burnside; James, youngest son.
2. William Stuart (b--??, d--1768), lived on Cowpasture, now Bath or Rockbridge Co. he m--Margaret Usher, descendant of English aristocracy (her two sisters Jane
Ann m--Loftus Pullin, Martha m--Col. John Dickinson, all of section now Bath Co.). William's will was made Jan. 12, 1768--proved Nov. 18, 1768; his brother John was his executor. ch: Ann Stuart, m--Thomas Osborn; Mary Stuart m--Andrew Shaw; Eliz. Stuart m--John Patton; Francis Stuart; William Stuart, infant(records show this to be the son of William's brother, John). William Stuart's first bequest is to his sister, Jane, to whom he leaves "father's town lands".
3. James Stewart (Stuart) settled on the "Lewis Land Grant", on a br. of the Cowpasture River--1747. This branch of the Cowpasture has since been called "Stuart's Creek". Records show that he was a business partner of Ralph Laverty, who owned the adjoining farm. James was killed by the Indians, Feb., 1757, and his son, James, Jr., was carried into captivity but was later restored to his family. James, Jr., was then a lad of about 13. James, Sr.'s wife was Ann , and she was made admnx. of husband's estate Nov. 17, 1757 (Order Book No. 6, Augusta
Co. records). By Sept. 24, 1763 the widow had m--again to Thos. Armstrong.
His ch, minors at time of father's death were: James, Jr. (Indian captive--but returned to family), he chose John Hamilton, a cousin by m--his guardian on Feb. 17, 1762--he was then 18 years old. He m--Isabel (probably Isabel Elliott, dau--of John Elliott; after first husband's death, she m-- ............ Barker); James went
with brother Ralph to Tygart's Valley (now Monongehale Co., W. Va., where he d--1777, probably while in militia service). Ralph Stuart chose as his guardian Robert Stuart, no doubt a relative--1762; he was then 15. He also went to Tygart's Valley and became a prominent man there. He was Capt. Ralph Stuart of the Revo; d--1792. John Stuart chose as his guardian Henry Murray; he was then 14. This was Feb. 17, 1762; he seems to have remained on homestead, or in Augusta Co.
4. Jane Stuart left estate by brother William, m--William Marshall--no other records.
5. Rebecca (sometimes called Eliz., probably beacuse there were so many Elizabeths; her name really was Rebecca), m--Ralph Laverty, business partner of James Stuart, and pioneer settled on Cowpasture River "Lewis Land Grant". He seems to have been a man of some means and prestige--was a constable in 1748; Rebecca d--prior to her husband, who d--in 1792. Ralph m--2ndly--Jean, widow of Robert Graham (no ch of this m--). Ch of Ralph and Rebecca (Stuart) Laverty; Rebecca(who was left the homestead by her father), m--James Hamilton; Agnes m--William Haddon; Sarah, who was left the family Bible, by her father, m--Alexander