Dear P,
I'm glad to hear you are having success.
I rummaged around in the 1870 census in that region and verified that the 55-year-old, Kentucky-born farm laborer Sire Kirk and the 25-year-old Moses Oldham lived in the household of Kentucky-born farmer Albert Robinson in Blue Township of central Jackson County along with the rest of the Robinson family: namely, 37-year-old Sallie, 15-year-old William, and three younger children--all of whom were born in KY. If you are sure this is your connection to the one you seek, there is a definite Kentucky connection here.
Also in the same region of Missouri in the Johnson County seat of Warrensburg in the Eades Hotel there was 45-year-old painter born Virginia named Malcolm Kirk;
and in Big Creek Township of NE Cass County another Kirk family, and somebody in Bates County south of that, too;
and in Saline Township of north-central Saline County the household of 55-year-old, North Carolina-born farmer David A. Kirk, Tennessee-born, 26-year-old Lydia June Carpenter, and two small Missouri-born children.

The Cass, Jackson, Johnson, and Saline County men were close enough to Colonel Jo Shelby's recruiting grounds centered in Waverly in northeast Lafayette County to have been part of his units, but I only pointed out men with southern birthplaces and ignored in the Kansas City area of Jackson County men born in more northern-leaning states.

I wish you continued good hunting, Bruce Nichols