I have recently spent a very pleasant afternoon with a distant relative, who up until this spring I did not know existed!; in the family history centre in Haddington looking up OPR's on the microfiche.I found and confirmed many of my ancestors and was able to get some names of witnesses to baptisms, some of whom may be in-laws to the parents of the child.
There is however a big gap of forty years in the parish of Ormiston as the records were lost in a house fire a East Mains, home of the church elder in whose charge the record book was kept.This has meant that I have been unable to confirm some connections.
Also there is a period of time where the handwriting of the book is more like arabic than english an is nigh on impossible to read.
Stick with the Kinghorn..there are many derivations even in one generation I have three different spellings of the same parent!Spelling after all never was an exact science.Look at the differences in English, Scots and American!