Ken, per your recommendation above I looked at the output from /shared/tmp/iapp_output_0, and see this: {"text":"Success","code":0}. I also did a curl from the f5 to the Splunk server and connected successfully. I'm still seeing fail messages in the ltm log, and none of the virtual servers or pools are showing in the Splunk dashboard.
This is an awesome app, and I look forward to having it function properly.
Thank you!
UPDATE: Challenge resolved. I had to change from Direct Mapping to just Map and everything is now showing up.