After posting I completely deleted all files/refs, rebooted the server, and reinstalled it all from scratch, including the java.policy error. After signing the database I can load the application just fine, again. I see the Agent load message on the console, and I can again access and use the profiler pages.
As expected, attempting a heap dump gets an access denied, since the java.policy file is wrong. When I updated the policy file this time, it loads. (shrug) Musta had something in there I missed - forest for the trees and all that.
Thanks for your time...
- Rags