Time for another update here.
Today, I placed the order for a Ranco Digital Temperature Controller, as well as a Avanti CF62 2.2 Cu. Ft. Chest Freezer. I will be using the thermostat in line between the wall and the freezer to cause the freezer to idle around refrigerator temperatures, as is described here. This will save a massive amount of energy consumption.
The only catch is, we have to have a chest freezer in a tiny house with limited counter space. While this may be a little bit of a hassle, I do think it will be worth it to save as electricity as we will with this setup.
A little later, we will be bringing a check for 5k up to my uncle to pay for building supplies thus far as well as some upcoming costs for hardwood flooring, etc.
I've also gone ahead and ordered our heater, which will be an Empire 15,000 BTU Direct Vent (DV215). It is a direct-vent wall-mount 15000 btu propane heater with separate wall-mount thermostat. I am HOPING that means we have the option of installing a "smart" thermostat that can set different temperatures at different times, on different days, etc. While I doubt that the one that comes with it will be so intelligent, maybe it will atleast have an actual thermistor and can be set by temperature, unlike the on-unit thermostats which seem to be a simple 1-6 number adjuster with no temperature reading involved.