Full Bridge NAH To A Router - Will Ethernet ports on the NAH stop working?

You can full bridge the NAH. Your router would end up on port 1(10G) and the old Optik boxes on the rest. There are differences between the older Optik boxes and the new ones. The older Optik hardware has some advantages currently if you record TV. New hardware has more flexibility in that it runs AndroidTV apps. Getting upgraded to the new boxes if you already have the old ones is a bit more complicated. If you did somehow manage to get the new hardware, then you could skip the NAH. As mentioned before, you'd want to keep it on a shelf nearby for troubleshooting purposes if you have connection issues with your router.

When I was using my own third party router, I just had it connected to my T3200 and did not bother bridging my T3200. Never had any issues either when doing it that way. Depending what you plan to do with your network, and run on it, that may or may not work for you and the NAH.