Hi Paula
I had a wee peek at the 1830 OPR birth of Elizabeth and saw the witnesses too....and so not being able to resist wandering off.....found this interesting entry in the 1841 census.....
Name: James Renton
Age: 70
Estimated birth year: abt 1771
Gender: Male
Where born: Midlothian, Scotland
Civil parish: Inveresk
County: Midlothian
Address: Carnie Road
Parish Number: 689
Neighbors: View others on page
Household Members: Name Age
Alison Banken 20
James Banken 16
Jessie Banken 18
Peter Banken 14
Isabela Ranken 21
James Ranken 45
James Renton 70
so now I'm wondering if Jas Rankin and Jas Renton the two witnesses were these two living in the same household 11 years later?

k If we only had family relationships!!!!! I'd wager that James Rankin might have been married to a Renton gal......and there is that christian name Alison coming up again.
and then just to be further interesting.....here's a Renton family in Newton....
Name: James Renton
Age: 30
Estimated birth year: abt 1811
Gender: Male
Where born: Midlothian, Scotland
Civil parish: Newton
County: Midlothian
Address: Harelaw
Occupation: Ag Lab
Parish Number: 696
Neighbors: View others on page
Household Members: Name Age
Elizabeth Bennet 4
Alison Renton 65
James Renton 30
Another James....an elder Alison....dunno who the wee Elizabeth is at the moment but based on names and location I'd bet even more money they are connected to your Renton line.
Are we wandering too far away from the Melville search???? Hmmmmm...
Best wishes
Jean