Predominance Toolset in ArcMap

[LoriHatfield1]

I found a blog on github.com for creating the Predominance Toolset in Arcmap.  I have replicated all the steps and have the two geoprocessing tools:

When I run the Calculate Gap there are no fields available to select.  My input feature class is a subset of block groups with a few demographic variables. Has anyone used this toolset in ArcMap?  I know there is the option to map by this in AGOL, but I need static maps for many different areas at block group level. Any help would be much appreciated.