I was wondering if it's possible to install and run splunk as a different user id other than what is in the documentation to create username:splunk and group_name:splunk.
I think you can just chown the binary or directory that the daemon runs to whatever you like.
This will chown the entire dir
In this example, $SPLUNK_HOME = path to splunk's directory:
chown -Rf splunk:splunk $SPLUNK_HOME