Our Genealogical paths cross! My wife is a G(3) granddaughter of William Maxwell (1802-1862) his father John William M. (II) b. 1741, Ulster, Ireland, his father John William M. (I) (1719-1786) born in Ulster, Ireland, died in Rockbridge co. VA. LDS shows county Down of Ireland to be birth place.
The above John William M. (II) appears to be a brother to your James Maxwell, but I have James born 1750, where you show 1745. Unfortunately I have failed to source index a lot of my information, an error I now realize the importantance of.
There are other researchers with common interest, Audley was another brother and I have seen a work up on his family.
Also Thomas who married Mary Pemberton, there is a book in the Dallas Public Library ( maybe others ) that chronicles his history. He was a minister during the rev. war. and settled in GA.
I have printed a report from my Maxwell file before it is about 150 pages but it follows William, William Stephen, William Oliver, Hedrick, from 1802 to present. William Stephen settled in Falls Co., Texas in 1873 +/-.
William (1802-1862), his eldest daughter married Thomas Gay, I got the earlist generations from a researcher of the Gay family.