While I haven't found the father, I found a record that Margret McKnight had another child, James McKnight, born on 6th August 1918 in Creevycarnonan, again no father is listed:
https://civilrecords.irishgenealogy.ie/churchrecords/images/birth_returns/births_1918/01275/1528624.pdfIt says Annabella McCormick was present at the birth. It looks like Annabella might be Margaret's sister. I found the birth record for Agnes Heniretta McCormick/McCormack, says father is Daniel McCormick/McCormack and mother is Annabella McCormick formerly McKnight:
https://civilrecords.irishgenealogy.ie/churchrecords/images/birth_returns/births_1911/01543/1624743.pdfI have not been able to find their marriage record yet but I found a Census record for them in 1911 living in Cluntagh, Crossgar:
http://www.census.nationalarchives.ie/pages/1911/Down/Crossgar/Cluntagh/239355/It says they were married for 3 years and had 2 children but I cannot yet find the birth record for their other child, just Agnes.
What I would like to know if anyone can find it, if there is a marriage record for Daniel McCormick or McCormack and Annabella McKnight? That might have Annabella's fathers name on it. It says on the census record they were married for 3 years but I cannot find a record between 1907-1908 or at all. Can anyone help?
I found this record of the birth of a Margaret McKnight in Killyleagh 1880 to a John McKnight and a Margaret Matthews, but I don't know if this is the same Margaret McKnight I am looking for but its possible since her father is listed as John McKnight a Joiner and the Margaret McKnight I am looking for, her son, my grandad was John McKnight, and he was also a Joiner:
https://civilrecords.irishgenealogy.ie/churchrecords/images/birth_returns/births_1880/02889/2058578.pdfI also can't find what happened to James McKnight if anyone can help me with him?
Edit: I realised I had a photo of Daniel McCormick and Annabella's grave I took in 2017 in Killyleagh when my dad and I went looking for my grandads grave. At the time I never realised it was their grave and my grandad John was buried in the same grave, says on the headstone he is their son, so looks like Daniel and Annabella may have adopted him as their own son, which explains why my grandad went by the name McCormick and not McKnight when he got married.