Yes, this product requires a standard 115v AC outlet.
Yes. You definitely need one for each.
I don’t know if your control box has the same pin connector configuration as the Rheem. If I your control box has a pin connection at the bottom right corner on the control box. Couldn’t get a picture without moving the washing machine. Hope this helps
Yes, in the instruction manual it states to just turn the front panel temperature control knob all the way off and then to the desired temperature.
You do not have to use the wi-fi feature so no, you don't HAVE to buy it.
I understand that Nest has a partnership with device.
The app does not appear to allow for that capability. You can only set the current temperature up or down.
If I were you, I would not purchase it anyways. It does not work as advertised, and has several issues. I am unable to adjust the temperature above 120 degrees, which is too cold. I also keep getting a water leak error, and the water probe is not even in the water heater pan yet, it is just laying on the dry ground. I disconnected from the system and raised my temperature manually. Much happier with my water heater now.
Your savings are dependent upon the heat setting you put your water heater on.