So, I think I've found the problem, and I'm not sure if I just misunderstood the documentation or if it's wrong... but it seems there is a problem with interactive setup:
Running hyperic agent with interactive setup in Linux breaks directory permissions (noticed this in ../hyperic-hq-agent/data). So, I changed owner and group for data, restarted the service and that seemed to work for a bit, but then I started to get JVM errors, and it would continue to show unavailable.
So, I completely removed the RPM and platform and started fresh, but this time configured it manually through agent.properties.
1. Installed RPM
2. Adjust agent.properties
3. service hyperic-hq-agent start
This produced the result I was looking for, and permissions on the data directory are now correct, nor am I seeing JVM errors in wrapper.log