Unfortunately I have no information on the parents of John McKelvie but I do have a McKelvie connection from the same area of Ayrshire but a little later than 1807. McKelvie is a relatively uncommon name so I feel there must be connection. I have a John McKELVIE who married Annie WAGSTAFF in 1846 in Loudoun. They must have settled in Newmilns which is near Riccarton and Galston as some of their children were born there. They were; James Wagstaff McKelvie b 1849, and Jean in 1853. The other children were born in Loudoun including two sets of twins. The last child was Margaret Hamilton born 1867 in Galston. James Wagstaff McKELVIE married Marion STRACHAN in Dreghorn in 1872. I suspect John above is related to your family in some way. What do you think?