Most of your information concerning Alice Applegate (b.ca. 1771) seems to be quite accurate.But I do not believe your reference to Mercer County is quite correct.The Applegate and Wall families were among the first pioneer settlers of the region of present-day southwestern Pennsylvania which is now part of southernmost Allegheny County.Many of their descendants still live in this region, and the pioneer homestead farms that they cleared were held by Applegate and Wall descendants until the early 1900s. When the Applegate brothers came to western Pennsylvania several of them settled in "the Forks" in what was soon defined as Rostraver - but today would be called Forward Township.The county lines were redrawn, but some of the family stayed on those farms.Several generations of the families were buried in family burial lots on their home farms.
Alice Applegate married William Wall as her first husband.He died in 1799 and they had a son, James Wall who was born in May of 1794.James died in 1850.He married Rebecca Pangburn, the eldest daughter of Williams and Elizabeth (Applegate) Pangburn.
The Wall family trace their lineage back to Long Island. The marriages between the Wall and Applegate families extended over many generations creating a complex knot of relationships.