It is a good starting point having 2 real IPs, never knew there were fake IPs on the internet ;-)
What are your options:
1) install the "real" NVR onsite, next to each camera, let it record the main streams and substreams
2) install a "dummy" NVR next to your monitor, and let it connect to the substreams of each camera to reduce bandwidth usage
3) in case you need footage, you can either download it from NVR#1, or go onsite next to NVR#1.
Just my 2c.
In any case: use a VPN with a huge compression rate to reduce bandwidth at all cost ;-)
Good luck!
CC