Uconnect 8.4 Engineering Menu Instructions
 

I see lots of posts about how to access the engineering menu to perform a reset on the radio but haven't found any information on using the various other options (diagnostics, etc).

Anybody know if there is a guide floating around on it?

You really don't need to access the engineering menu in order to perform a hard reset. On your screen go to Settings -> System Information -> Reset to Factory Default. There are a lot of things on the engineering menu that will really screw you up if you don't know what you're doing.