1 new of 290 responses total.
First, re #10: yes, WiFi works through walls and floors. I use it between the older (wired) computer LAN on the second floor and the cable entry point on the first floor. I have, when I've chosen to check, found other WiFi servers somewhere nearby (because they haven't blocked their SSID signal). The range might be up to a couple of hundred feet. I also have X-10 over the powerlines, but for one-way control only. I use a stand-alone transmitter that I program with my computer. I don't like the idea of two-way systems that require that the computer always be on. My X-10 system has been very reliable. It controls some 30 lights. Once in a while a light doesn't go on or off - some noise burst, probably, has interferred with the system. What you can do is program duplicate on or off signals a minute apart to reduce such rare malfunctions even further. The X-10 system offers several benefits. I found that as soon as I had it installed that our electric consumption took a significant dive. The reason is that lights don't get left on accidentally. I also run the outside lights slightly "dimmed", which increases their lifetime considerably. In addition, the X-10 system makes the house appear occupied when we are away. It includes a random timing feature so the same lights go on and off at different times within a window of an hour or a half hour. I am considering getting a drape drive, but primarily as another security feature. For that, I can justify $100.
You have several choices: