James Johnston/Millie Wagoner Iredell County NC

I am looking for birth and death information on my 3rd great grandparents James Johnston born ???? in Belfast Ireland died ??? in Iredell County NC. Wife Millie Wagoner born ??? in Lincoln Co NC died ??? in Iredell County. 2 sons that I know of Samuel Edmond Johnston (my 2nd ggf)buried at McKendree Chapel Iredell Co. and son James H. Johnston buried in Davidson College Cemetery Mecklenburg County. My great grand father John Alexander Johnston is also buried at McKendree Chapel in Iredell County. I'm thinking that James must be buried there as well but haven't found a headstone.