Hi
I am researching the McQuillan's in Edinburgh - Philip (Philp) and Margaret Hind/Lind/Kind. Their daughter Margaret (Maggie) was born in Edinburgh about 1879 and was my wife's maternal grandmother.
There is a lot of information in the post correct for my tree (see Genes Reunited, ancestry.co.uk)
I have lots more information.
However, the wife of Philip is a major problem. On the marriage certificate for Margaret McQuillan (Philip's daughter) to James Allison on 22/7/1898 there are amendments to the parent's names. The grooms mother is changed from Margaret Allison M/S (Maiden surname) Leighton to Martha Allison M/S Leighton. This is stated as a clerical error. Also on this certificate, Margaret's parents are listed as Josuah McQuillan and Margaret McQuillan M/S Lenn (perhaps Linn). I had been searching for Margaret Lenn.
However on viewing the certificate at New Registry House in Edinburgh, there are other amendments which I could not print. Martha Allison M/S Leighton is changed to Martha Reid, while the Josuah becomes Philip and Margaret's surname changes from Lenn to Hind. I have struggled to find their marriage anywhere and have seen the one you list to Margaret Mullen but have problems reconciling it. I have found a baptism for a Philip in Co. Down, Northern Ireland in 1843 but not confirmed. If this is correct, his father was John McQuillan. If you have confirmed that Robert's parents are Philip and Margaret Linn, then I have a problem with the daughter Margaret's parents. I will need to check the marriages of the other children of Philip and Margaret to see who the parents are. I too believe that Philip was born around 1843 not much earlier.
McQuillan is sometimes written as McQuillen and McQuillian
Robert