Donald,
Sorry, but I have not gone back past William & Christian als Lawrence, and to do so looks to be quite a problem. My interest in the family was 1) William Costean (b.~1700 to Wm & Xtian?) married Jane Skillicorn in 1722. (there was a Marriage contract). William died in 1725 and Jane married William Lawson 1735(they are two of my 5x G Gparents)- 2) William Lawson's sister Isabel had a child in 1726:
Lonan Parish Register 1726: Phillip, Illegitimate child of Danl Costean and Isabel Lawson Bapt. July 24th
I was looking for confirmation of the Costean family in the Wills, and assumed that the Daniel who was the father of Phillip Lawson was also the brother in law of Jane Costean als Skillicorn. Isabel Lawson married James Kelly in 1741
Rgds
John