I am descended from this same family.
William J Ghrist's daughter, Cora Mae is my great grandmother.
From what I have seen there is some confusion as to who Johnson Ghrist's father was. It could have been Joseph Ghrist or possibly William Ghrist. The Ghrist's all had large families and named all of thier children the same names so there are several, Johnson's, Joseph's and William's.
I came across this reference to a Ghrist Will that suggests that this may be our Johnson Ghrist referenced in the will but there is no way to tell for sure which one.
Ghrist, Joseph, Washington Twp. dated 10-5-1826, prob. 11-28-1829
daus Rebecka, Orpha, Thirza Clana, Margaret Bayly, Lydia Downs
granddau Margaret Simpson
grandson Johnson Ghrist
executors nephew Joseph Ghrist, son Joseph Ghrist
witnesses James Binns, Thomas Beeton
There were some older posts about who Johnson's father was and it seems nobody knows for sure.
I communicated with another Ghrist relative a few years ago and she is having the same issues.
I hope we can get this figured out at some point.
You probably already know this but Ayres is buried in the Dickerson Run Union Cemetery in Fayette County, PA near Dawson and is a Civil War Vet.
If you make any headway please let me know.