Maybe this will help some on Thomas. Definately he was not the father of William who married a Shirley. Definately he married 3 times.
1744 Thomas McGuire taxed in Hampshire Co., VA
14 August 1749. Northern Neck Grants, reels 288-311. Frederick County. Description: 350 acres Lot No. 19 on the Wappacomo or Great South Branch of Potomack. Source: Northern Neck Grants G, p. 270 (Reel 292).
1764 July 25 Hampshire Co., VA/WV deed book 1 page 263. Edward and Susanna McGuire are setting up mortages on some land. One piece was sold to Edward by Thomas McGuire. This land on Mill Creek and contained 352acres.
1765 June 12 Hampshire Co., V A/WV Deed book 1 page 282 Thomas and Elizabeth McGuire, she the relict of John Parker, are on the partition deed along with all the Parker children. The girls are married so it appears that all the children are grown. Thomas signs with a mark.
1768 Thomas McGuire patents 400a in Hampshire CO., VA [Northern Neck Grant Book Y pg. 322-333]
1777 Mc Guire, Thomas: Ohio Co., VA [Brøderbund Family Archive #310, Ed.1, Census Index: Colonial America, 1607-1789, Date of Import: Aug 1,1998, Internal Ref. #1.310.1.1151.126]
1778 Washington Co., PA tax Thomas. [WP Gen. Mag. vol. 12]
1781 Hopewell Twp., Washington Co., PA 500 acres [PA Archives vol. 20]
1785 Hopewell Twp., Washington Co., PA tax list.
1787 Hopewell Twp, Washington Co., PA
1788 444 acres surveyed. [PA Archives vol. 20]
1790 Washington Co., PA 1 5 3 [five sons 1774-1790 and two daus]
1791-1793 Hopewell twp., 400 a.
1793 left will
1797 Thomas and Elizabeth, minors of Thomas, over 14 choose Mary McGuire [Washington CO., PA orphans court, Apr. 10, 1797, Book A/B pg. 23]
Thomas lived in Hampshire, VA prior to moving to Washington Co., PA.His son William remained in Hampshire. Supposedly William received land from his stepmother Elizabeth. This land had been part of the John Parker estate. So it looks like Thomas had three wives. The mother ofthe first three children, Elizabeth, then Mary Randalls who was the mother of the rest of the children.