See http://docs.zenosslabs.com/en/latest/
This tutorial on ZenPack creation covers extending device classes and adding properties, and then showing them. You could also create a custom modeler that populates some of those custom properties automatically if that is possible in your setup. The nice thing is you could wrap all these modifications in a ZenPack for ease of re-install/transfer.
The tutorial also covers displaying the information.
There is about 8 hours of video, it's quite in-depth.
Manuel