I don't have the parent names for my John Good.He could very well be your James Good's brother.Mine was born abt. 1766 as I have the death cert. for his wife, Elizabeth Rennie who died in 1858 at 92, so he must be close to 1766.
I see your James Good and Mary Brown were married 24 Jan. 1790 in Crichton and Children:
Elizabeth Good Chr. 24 April 1791 Crichton William Good B. 31 Dec. 1806 Chr. 22 Jan. 1807 Crichton James Good B. 14 Arp. 1793 Chr. 1 May 1793 Crichton Ann Good B. 2 Nov. 1804 Crichton Joseph Good B. 14 Sept. 1802 Chr. 3 Oct. 1802 Crichton John Good B. 14 Feb. 1790 Crichton
Both families have similiar names, so maybe down the road we can find their parents.