I am liking the idea maybe dome cameras with IP67 Rating and a low power consumption NVR/XVR and a UPS System. Wireless camera can work as well and battery operated/solar powered Camera. One concern is probably with the scenery always changing, camera performance and quality might deteriorate as...
General Firmware is probably the Factory Default firmware. Dahua Suppliers have their custom firmware that might work specifically for the devices they are offering only.
Can you try restarting the recorder if the status will change? You can also go to network settings of the recorder and do a test if it can ping the network gateway?