@Stephen WallaceBut Stephen, this Harbor Freight coupon says I get 90% off my of one item and they'll throw in an air compressor. :)

Another cabin had placed the hot tub in a remote area under the deck, near the central a/c compressors, downstairs and away from the main hub of the home.

You can get a system with one compressor and multiple "heads".

I got very "lucky" for having another unit's AC compressor to stop functioning in the middle of this / at the same time.

They have mini-split systems now with 4/5 units per compressor so you'd likely only need two compressors.  

The report stated:Plumbing tested with air compressor and system did not hold 35 psi for at least 15 minutes.I have no idea what this could indicate...does anyone have any experience with this?

He doesn't say anything to me but walks around the side of the house to the AC compressor and bends down and studies it.

Sometimes a roof goes bad or the compressor in the heat pump goes up causing a CapEx expense and sometimes investors use property management companies to detach themselves from the day to day issues of being a landlord. 

For example, last year, I was out of the country, and I had a compressor failure on an AC.  

.  ;-)  I have had an air compressor on an AC unit blow out.