Hi Dean,
You're more than welcome. As far as if they will communicate with one another, yes they can but I would not recommend streaming the HYBDVR to the NVR. The best thing you can do is allow them to both operate on your network and watch them in SmartPSS simultaneously, or watch them in your browser.
Yes, as long as they are on the same network you can certainly open DIFFERENT ports to the machines and watch both of them with the same WAN address just using the corresponding port.
If you want to use the web interface you can. On the LAN each DVR will have its own IP, then on the WAN you will use the same WAN address (as long as the DVR and NVR are on same LAN) just have to specify the correct port.