Add my vote to using prefab kitchen cabinets. They're extremely versatile and fairly economical. In my darkroom I have used them for both wet and dry side. The units are bolted together and are rock solid.
On the matter of temperature control, I have two units, an older Powers unit and a Hass Intellifaucet. The Powers is a mechanical device like the Leedal units. The Hass is electronic, monitoring the output temperature and using stepper motors to control the supply to maintain a preset temperature. Both work reasonably well. The Hass is very simple to use; an LED comes on to indicate that the correct temperature has been achieved. (I still have a good old analog thermometer on the output anyway.) If buying new, I would recommend the Hass unless you can find the other type for substantially less. When you do buy, be sure to consider your flow requirements as both types operate normally within a specified flow range. If I recall correctly, I bought a low flow rate version of the Hass.
If buying a used temperature control, especially the mechanical variety, be careful. If it's been used without proper filtration or if the water supply has contained a lot of minerals or if it's been used for fluids other than water, it may be shot.
Having said all of the above, if I had it to do over again, I probably would have saved my money and not bought any automatic temperature control. Both the mechanical and the electronic (Hass) types require a reasonable temperature differential in order to work. Said another way, your cold water supply needs to be several degrees below your target temperature if the device is expected to stabilize. I live in the San Francisco Bay area and for much of the year my cold supply is not as cold as I'd like. Of course, the solution is to use higher developing temperatures. But I've found that for black and white work a plain old manual faucet with a thermometer on the output allows me most of the control I need. Your situation in Owensboro may be different. But unless you need a large amount of set-and-forget tempered water for a specific process, you can save yourself the money.
In-line filters for the cold supply are available from Home Depot for around $35 or so, I believe. Don't know about hot side filters. I found a brass filter housing on Ebay and am using it for my hot supply.
If you're happy with the ABS sink and not inclined to get into construction, go with it. You can always upgrade later and in the meantime you can get to the business of printing. My sink is mounted on pre-fab kitchen sink base cabinets which are offset from the wall by about 8 inches or so. The supply lines run along a narrow shelf in back and through risers to a board mounted to the studs behind the sink. The mixing controls are mounted to the board (melamine-clad particle board). A shelf at the top of the backsplash covers the offset and provides a place to set things when working at the sink. Don't overlook the need for a place to set stuff. Horizontal space is always in short supply!
The supply enters the room underneath the sink through a washing machine type shut-off (one lever controls both hot and cold on/off). An eyebolt connects a dowel which allows me to conveniently turn the supply on or off from the front of the sink. Naturally I keep it off unless I'm working in the darkroom.
Vacuum breakers are required only when there is a possibility that loss of the supply might result in contaminated water being siphoned back into the line. In a commercial environment it's required because of code. Chances are you don't really need vacuum breakers at home. But ultimately it depends on how you're using your plumbing.
Your floor plan indicates a closet. If that will be used for clothes, it will add to dust problems. The bedroom which became my darkroom also had a large closet. I removed the doors and built a counter in the space to create more usable workspace. Of course, I also lost a lot of storage space in the process. But then, I'm not married.
My Verito page
Anyone can appreciate a fine print. But it takes a real photographer to appreciate a fine negative.