I have just started looking at this site and hope you are still looking. My husband is descended from Charles Dunlop via his son Charles (married Mary Carter).
You mention 2 things of interest to me...
Firstly that Charles and Mary Carter had more children than Charles and John. I have never managed to find any extras so would love to know what you have found.
Secondly, I had suspicions that Charles' parents were Charles and Katherine Gilmoure but couldn't find any definite proof of this. If you have I would love know where you found it so I can source them properly into my tree.