Basically, the lesson here is really simple:
If you want to be able to accurately control your AV devices, then you need to buy devices that are targeted towards the Custom Installation market. Companies like Denon specifically have a model line for this, (for Denon, this is the CI line, look for the CI next to the model numbers, e.g. 2312CI). Companies like B&H Photo and Video not only sell TVs and AV equipment with workable control ports and protocols, but they also have people who KNOW what an RS-232 port is, know if a given TV has control ports, etc. and will give you a much smoother experience.
Don't buy your stuff from Best Buy, if you don't know what you're looking for, guess what? the idiots who walk around the floor don't have a clue, and will not be able to help you.
and Don't go cheap for the sake of being cheap, you will get burned. Full stop.