I think the confusion lies in the fact that there are so many Sr's, Jr's, etc. in the family line.
Mary was married to Parker Adkins (1762 - 1857). They had Silas 1792, Preston 1799, Margaret 1801, Grover 1802, Larkin 1803, and Mary "Polly" 1807.
Blue Sky was married to Parker Vincent ( 1720 - 1792). They had Littleberry 1767, Charity 1768, and Irene Jane1772.
As far as Hezekiah is concerned, there are at least 2. Pvt. Hezekiah 1759 - 1842, and Hezekiah Jr. 1795 - 1876.
I do not have a Nancy Harley connected to either of the Hezekiah's.
William & Elizabeth were the parents of William Jr. 1712, Richard 1717, Joseph 1723, Sherwood 1728, Henry 1730, Rueben 1731, and Elizabeth 1732.
I haven't gotten that far on my wikitree yet so I can not answer the rest of your questions just yet. I hope this helps