re: "Since you own an Ultra I'm going to assume you understand that these remotes use WiFi"
The fact that I own something doesn't mean I have a clue as to how it works. 😉 I actually don't have a handle on how the various remotes work (IR, RF, wifi), or which remotes for which models work in what way. That's one of the variables that I assume comes into play in the scenario I'm trying to put together.
re: "square footage of your home, location of the second TV and router could play into the scenario as well as whether both TV's will operate simultaneously"
Location of the second TV (with its own Roku) will be within 10 feet of the first. The router is in the same room as both of them (well, in the closet). Both TVs/Rokus will operate simultaneously (that's why I need to make sure that each Roku only responds to its own remote). Since everything is in the same room, square footage of the house shouldn't be an issue, though.
re: "see who else in your nearby area is using the same WiFi channels. If your channel is used by others, I'd recommend you log into the router and switch to one with less congestion. I mention this since WiFi congestion is the #1 problem with connectivity."
Luckily, that will not be an issue for me. I have no connectivity issues, and houses here are somewhat far apart. My various devices see no routers other than my own.
Thanks for your input. 🙂