The information about Renner being taken prisoner came from the Camp Chase Records, having said that no source is 100% accurate. However, when Willis showed up as also being a prisoner from Fort Donelson, and with the 51st Virginia Militia, you have to start thinking, were there others? It could be a mistake or it could lead to new information about Donelson, as the 51st VA Inf. was at Donelson, but no one has any records of the 51st Va. Militia as being there. As you know their history is incomplete.
However, you were right about the Willis marker at the CCCC as being incorrect. It should read 51st Virginia Militia and not the 51st Virginia Infantry. I have located the material and information from which the stones were made in 1907. I will be in Charoltte, NC shortly and find the answers as to why so many mistakes were made at the Camp Chase Cemetery. Probably just like today? But information in and bad information comes out.