Thanks Let It Snow! The links were very helpful. So it looks like the system works over the house's existing wiring, which makes sense why one controller can operate a number of different switches.
I guess my questions are around how to remove the system. I would think I could just remove the switches and complete the circuits in the basement and attic then wire in the new Caseta switches in the wall boxes. I might have to tie together two of the lights to one switch unless I want to expand one of the wall boxes (since I have four lights and only three receptacles). Does that sound right to you? Anything else I should be thinking about?
I'm not sure why the wiring in the attic has three switches (controlling only one set of lights), but suppose I will figure that out when I take it apart.
The Leviton System can be installed on any existing switches, as long as a neutral wire is available at each location. There is no special wiring required. It's possible to completely remove it and go back to normal / conventional switching.
The Caseta system is easier to install on a single pole switch. In most cases you take out the switch and install the Caseta - no neutral required.
> Download the App to your phone or tablet.
> Install the Caseta internet hub at your router.
> Create a free account
> Select Add Device on your phone or tablet
> Hold the bottom button on the Caseta for ten seconds
> The App recognizes it, you name it, and it works.
> You can now control it from your phone or tablet, create groups of switches, create schedules of off/on
> Add it to Amazon Alexa or Google Home for Voice control
> "Alexa, turn on the kitchen", Alexa, dim the kitchen to 43%", "Alexa, turn all lights off"
Three-way and four-way switches are a little more involved but easy to install. Start off with single pole and graduate to 3-ways.
Here's a link to the advanced installation guide