Hello Bobby, a lot of good information, I have some of this already, but not all.
And I have something for you!
There is an additional female child named "Thelorn Pool" born in 1763. She is born to Sarah Scott but possibly after William Jr has died, which would explain why she is not listed in his will. Sarah Scott remarried to Richard Rivers, and since Thelorn's last name is Pool my assumption is she is the daughter of William not Richard.