The Wyze App is used to control ALL Wyze IoT ecosystem devices, to include the Thermostat. It is the only App needed for all Wyze devices.
You can install as many Thermostats as you like. Just recently I saw a user that had like 8 of them installed. They can even be in different houses in different states.
Not a problem.
That’s not possible yet. The three thermostats will operate independently of each other. They are not linked together.
It is best to run the compatibility checker to make sure your system is compatible first. Zoned systems may not be compatible.