Briana,
You raise some great questions. I can add some pieces of information, but nothing that really helps in the search for Matthew Gallaway/Galloway’s parents. Another researcher and I have been searching for documents relating to his reported Revolutionary War service. We have hit quite a few dead ends in the search for documents, but have come across some tantalizing pieces of information that have some clues.
1. Irene Dabney Gallaway. Like you, we researched her to find out where she got her information. She spent her life as a librarian in Texas and her home town of Fayetteville, Arkansas, and appears to have written a number of other family genealogies. We looked for her papers at both the Library of the University of Arkansas and at the Fayetteville Library, where she worked for a long time, but neither place had them. It seems that a librarian who did so much research would have left her papers to some institution, but we haven’t been able to find them. (Her line appears to be daughter of John Bell Gallaway, son of James Levi Gallaway, son of Anderson Gallaway, son of our Matthew). She did make a comment in her history that she could not find a record of Matthew’s war service and suggested he might have been a Tory, but she later recanted that in a 1948 letter to the DAR regarding the application of a relative, Anne Henry Sawyer. (She said in the letter that she wished to atone for her earlier statement!)
2. Georgia Land lottery. You asked if anyone knew if he had received the Georgia land from the lottery. A fellow researcher did contact the Georgia Secretary of State to find out if Matthew did receive the land. They reported in a 2008 letter that his name does appear in the 1806 list for the 1807 lottery, and that he did get a grant but he did not take up the grant and the land reverted to the state. (He was on the eligible list for the 1805 lottery, but “drew two blanks” and didn’t receive a grant for that one).
3. Mary Polly East Gallaway. You noted that she supposedly married an Elder Henderson and lived in Walton Ga. I am pleased to report that I did find her living with a Rev. Hutchinson in the 1860 census in Walton Ga, at age 93! (wow, he was 84); she appeared in the 1850 Walton GA census as age 80, living next door to the Lester family, who may be related to the Emily Lester you identified as likely to be Mary Polly's granddaughter and mentioned as a source for the Tait Gallaway reference in the Irene Dabney Gallaway book. So I have to read over your suggested dates for the possible interaction between them that would lead Emily Lester to be the source for Tait etc.
4. Other references. Matthew appears to be mentioned, either by name or as a paternal grandparent of his many descendants throughout the South, in various histories and biographies of families written in the late 1800s or early 1900s. I’ll try to do a list of the ones we have found, but I can’t tell if Irene Gallaway was using these histories in her 1908 research or whether they are independent of her. Will post those later.
One hope is that if we can identify Matthew’s father and perhaps other brothers, that might lead us to his war record and provide evidence to have DAR restore him as a recognized patriot. (As indicated in other postings, he is no longer recognized because the only source right now is the GA land lottery and that is no longer allowable as evidence of revolutionary war service -- apparently it was open up to non-soldiers at some point.)