I'm glad to hear that the 7550 Modem/Wireless Router is normally stable.
I do not fully understand your suggestions.
The manufacturers of both the Thermostat and the IP Camera provide a service for Dynamic DNS. I don't have to do any port forwarding. All I have to do is assign a unique port, and their service handles the rest.
I also don't know how to shut off Auto Channel. I can look at the internal registers of the 7550 when I am at my 7550's location, but not from here (400 miles away). I also cannot find any user's manual for the Frontier/Netgear 7550.