If you use option 2 there will be only 1 thermostat to decide the temperature, so it will probably need to be in the master bedroom. 

If you're looking to reduce the utilities only low flow faucets and shower headsdual flush toiletslower the temp on the water heater.Make sure the HVAC filter is changed monthlyPreset thermostat.

I was reading something similar to what you are suggesting is that they take a little to heat up.Do you run the ones with individual thermostats and if so do you find complaints about tenants having to set each room or vice versa do you set a each level on a seperate thermostat.The unit I am looking at is about 900 sq ft as well and I am hoping to heat it exclusively with electric but want to be sure ahead of time that if I spend the money it will work.

Don’t crank up the thermostat every time your real estate investment gets a little chilly.

.- water efficient heads- Chicago controls thermostats- coin op laundry was our move this year- big ticket item but I am still a kid when I empty the quarters 👍 - make room for parking on the property- additional $- turn the boiler down.

Another thing to consider is you can purchase a thermostat controlled plug/switch that can alleviate anyone having to switch on and off the heat source.

Your county building dept will have physical requirements for a separate dwelling unit (such as thermostatic control, accessibility to the breaker box, basement window egress and fire separation.

You can also add wifi lights and thermostat, allowing you to control the lights and temperature at a distance.Only allow them to enter the premises in your absence after they email you a photo of their driver's license and if it is more than one person, get photos of all of their driver's licenses.

-There is a 1200sqft unit on the main floor and 2x 600sqft units upstairs-There are two furnaces and two thermostats, but both thermostats are on the main floor, and the furnaces/ducting are split side to side. 

Rather than starting a new thread I will tag on to this....I have a couple of rentals with a similar situation as original poster, but they are 2 units, under 1 heating system, controlled by 1 thermostat in the 1st unit.  1 property is a gas furnace1 property is an oil furnace (bills have been painful this winter)Gas Furnace Property- I had an HVAC company check it out, specifically with converting 1 of the units to Mini Split system.