Jenkins Artifactory Integration - Custom Maven plugin creating dynamic version/build
I figured out how to get this job to run which took a number of very specific steps:

1) The Maven3-Artifactory plugin will simply not do what I need it do here.  I still need this in my job though to actually execute my custom maven plugin from the project POM.  I configured the Build Environment for this plugin to NOT upload any build artifacts to Artifactory.

2) I added the Generic Artifactory plugin that has the responsibility of taking the zip artifact from the Maven plugin and uploading it to our Artifactory repo.  I struggled to define an upload FileSpec that worked correctly.  I ended up using the Legacy Patterns option where I could define the upload artifact and the repo location based on a number of Environment Variables that have been already defined for me previously (more info on this in future steps).  The Download Details are effectively empty.

3) The first Build Step is execution of the Maven build.

4) The second build step is execution of a custom shell that will parse the maven build artifact zip file for information that is needed to derive the version number.  It then injects this version number into a temporary property file in the root of the job workspace.

5) The third build step uses the Inject Environment Variables plugin to put the temporary property file into environment variables used by the Generic Artifactory Plugin Legacy Pattern.

This seems to work well as a solution for my situation.