Thanks for your input, John and Frances,

I agree the William Kelly 1752 will does fit the family of Margaret Kelly who married John Skillicorn. However, I am reluctant to just chalk up Frances' summary as a misreading of Kelley/Killey without a further checking of the will. I would love to be able to check it myself, but am no longer able to do that.

I also wondered if there are MIs that will help sort out this family.

I was interested in your comment that William Kelly had a brother James. This would indicate that you have identified William's parents, or perhaps his siblings?
Is this William (d 1752) the one who married Ann Hogg (Lonan May 10, 1719) and had a daughter Margaret with her? Did William marry a second time after Ann Hogg's death (bur Lonan July 20, 1721) It seems likely, since he had a very young child to take care of, but I haven't located a likely marriage in Lonan, nor a likely burial for a possible second wife.