Tracking down the John A Simpson of the 7th MO Cav (Union) has led to the discovery that this gentleman was a native of Missouri enlisting in Brookfield, Linn County, MO Apr 25, 1862, age 30, initially into the 7th MO Cav then transferred to Co M, 1st Regt Cav Vol under Captain Prewitt, and died at the post hospital of disease at Pine Bluff Arkansas Dec 11, 1864. He is interred Section 3, Site 2712, Little Rock National Cemetery. This obviously negates the John Anderson Simpson of Lawrence Co MO (aged 40 in 1861) being the above described person. So yes there were two John A Simpson's with daughters named Nancy A Simpson that ended up in Arkansas in the Civil War from Missouri. The hunt goes on.
John R