"With this in mind I believe the Southern Unionist, was too poor to own slaves and felt the secession was only to further slavery."

Not necessarily so.

There were many Northern Slaver owners who were in the Northern Army, the most notable was none other than U.S. Grant who owned slaves in Missouri prior to the War. And whose wife and her fathere also owned them during the War.

Also many of those Southern Unionist were first Confederates. We all know the story of the Galvanized southerner who took the oath to get out of prisons. Also, in Arkansas for example many changed sides when Little Rock fell. The same in Tennessee.

I believe that the majority of the Southerner in the Union Army were basically survivalist.

Also at that late date (1897) I wonder how they determined the orgins/residence of the soldiers, north or south? I say this with the knowledge that with our modern computers this is difficult to determine. And then you have Units like the 1st Arkansas US Infantry ( a southern state union unit) had a large number of men from Kansas and southern Missouri in it. Would those men have been counted as being southern?