If there is any standing water in the lines, when the temperature drops below freezing, that water will freeze and expand, likely bursting the line while doing so.3.

I had a cage welded and cemented over the outside AC unit on Tuesday.

So, while the same amount of heat (more, actually) will get taken out of the heat exchanger, the output temperature will be lower.

., I want to give folks the ability to set the temperature on their own.  

You can see and control the thermostat temperature from your phone from anywhere.

(1) Since it's in a freezer so it would be subjected to freezing temperatures. 

Besides all the snow that we are getting this year (here in Philly we had 5 snow storms and super low temperatures, 25-year low). 

Do you know of any ways I can get the temperature of the inside of the building without installing a nest or similar?

I'm getting condensation forming on a wall due to the temperature differential between the inside and outside. 

I agree with Jon, there are certain codes that one must follow when installing one of those, a licensed plumber is recommended but I've watched them replace mine and it didn't look like a big deal, if you can cut and weld pipes, it's pretty straightforward.