1) Buy a new pump
with a pressure switch built in.
2) Install an accumilator tank.
3) Install a valve(s) so I could determine which tank was in use (this could be used to help balance the boat vs water forcing you to heel greater).
4) Keep old pump
and use it as a washdown pump
(probably its intended purpose).
5) If new faucets are needed, I'd buy them from the hardware store vs the same thing from a marine store at a much higher price.
I think you'll find the new pump
already has "rubber feet" to help dampen vibration. However, any pump will still be loud when running. Relocating the pump would probably be best, or insulating around it might make it tolerable.
I'd guess the PO went cheap instead of doing things right!
Whatever you do, make sure the electrical power to the pump is OFF when you leave the boat. Several years ago when I was off fighting a war somewhere, I left my son to look after my boat. Although I left specific written instructions on how to take care of the boat, he didn't quite understand. I returned to find the 12v system switch ON, water pump switch ON, both battery banks drainded (and batteries shot), and battery charger
fried. He thought the dehumidifier was running but it turned out to be the pressure water pump. After new batteries and charger, I tried the pump and was surprised it still worked! My best guess is it must have been running for a day or two straight, completely dry, before it took out the batteries and charger.
Hope the project goes well for you. You may want to consider installing some sort of hot water heater while you're tearing appart and fixing the fresh water system. It sounds like you've got a very good start in having dual tanks.
Skipper, J/36 "Zero Tolerance"