A Word on Holmes' Slave Tunnels
That word would be: No.
At the time of the Civil War, and before, the Holmes campus was a bunch of trees. Covington didn't extend that far south.
You'll find most discoveries of tunnels had nothing to do with slavery, but were more likely built as a means to unload supplies from passing boats out of the weather, and out of the mud. Don't underestimate the prevalence of mud in older America. The Underground Railroad is a figure of speech, usually not an underground passage.