The Fitzwaters of Ohio

I looking to clear some confusion I have about the Fitzwaters who settled in Clermont Co Ohio. Most of the tree's I have seen basically show that all the Fitzwaters in the area can trace their roots back to a single Fitzwater family, that of Thomas Fitzwater(1766-1839) and his wife Lousia Coulson who made the trip from Whitpain, Pennsylvania. What is confusing is that I keep seeing another Fitzwater in the record books that supposedly was one of the first pioneers in Clermont Co., and had children with the same names as those of Thomas's. His name was William Fitzwater(1765-1841). He is repeatedly mention is Bryon William's History of Clermont Co published in the late 1800's., which lists him as a Revolutionary War veteran, a land owner and tax payer, and saids that he is buried in Miamiville Cemetery, which is the same place Thomas is buried.

Most of the trees show that Thomas had a brother name William, who has the the same dates as the one above, but they state that he stayed and died in Pennsylvania.

Does anyone know for certain who this William was and were he died and more importantly, what connection he has to the Fitzwater branch of Clermont Co, if any? Is William and Thomas the same person?

I would sincerely appreciate any help with this confusion.