Thank you very, very much for posting this document---in its entirety. I was aware of the text of the will, but never knew until now about the other materials in the file (proof of will, inventory, dispersements, etc.), and it is in these that I find one of my ancestors (Lovina Allard Oliver, pp. 2 and 3). I have for many years suspected, from strong circumstantial data, that she was indeed the sister of Mercy Allard Roberts and Mercy's siblings, but until now had no proof.
But now a few additions to your preface:
First, Mercy and her siblings were in fact the children of Daniel and Mercy (Bickford) Allard.This is proven by two 1835 deeds from Morgan Co., OH (Deed Book E, p. 515 and DB E, p. 531), wherein it is explicitly stated and sworn to by Daniel Allard that William G. W. Allard (Mercy Roberts' brother) was his son; prove one you prove them all.
Second, Daniel Allard was apparently born 1766 (not 1751), for on all censuses he gave an age indicating his birth in 1760-69.