"What kind of warranty do these outdoor beach/pool showers have?"
Stainless steel components have a 10 year manufacturer's warranty. The valves (as with any mechanical device) will eventually need some service. If the valve breaks or is faulty within one year of you purchasing it from us, the factory will furnish you a replacement valve.
"Which of the above models can I run both hot and cold water?"
The WMCH-445-ADA and the HC-4000-ADA pool showers are designed for use with hot and cold water supplies. With these units, you can run both hot and cold water.
"What is the difference between Model 1000 and Model 2000?"
Model 2000 and Model 1000 are similar, except that Model 2000 comes with a foot shower. The foot shower reduces the amount of dirt, sand, grass, leaves, etc. that can get tracked into you dwelling. The Model 2000 is (almost) a must for beaches and sandy areas.
"How are these beach and pool showers attached to the plumbing water supply lines?"
These beach and pool showers come with 1/2" x 12" stainless steel flex hose. They are connected by using standard 1/2" pipe. The water line should protrude about 1-1/2" out of the ground. Then it's simply a matter of connecting the two with a stainless steel braided hose.
"If I order an ADA compliant pool shower that includes a foot shower, will the foot shower have the metered push-button valve, too?"
The ADA compliant foot shower models come with push-button valves. at both main valve and at the foot shower valve. The hose bibbs and drinking fountains are push-valve or lever handle (ADA compliant).