One place to find soldiers who served in WWI from Fayette County is:
We have also provided an index to Uniontowns-Part-in-the-World-War. The information about the soldier may contain a photo, the parents’ names and address, dates of service, organization and rank. Maiden names of the mothers are rarely given. It also includes men in Dunbar, Masontown, Point Marion and Perry Township. The book can be found in the Pennsylvania Room at the Uniontown Library.
Another book is available online at the link below:
Fayette County in the World War by Frederick M. Hanes (Vandalia, Illinois: published under the auspices of the Fayette County Chapter of the American Red Cross)
World War I draft cards may be found on FamilySearch.org at: United States World War I Draft Registration Cards.