If they demand better performance, let them hire an A/C technician on their own dime and get a professional opinion, or they can terminate their lease early and move somewhere else.

property is currently in a reverse mortgage need $308k to satisfy. currently 3 units and wanting to remodel to create a 4th.Rural low economy market with high demand and very few rentals available in area.

There is growth in both of these markets, with major companies in each it causes a higher demand for rentals. 

Yes, the spring/summer season sees demand ramp up, but that doesn't mean a house listed in December won't sell.If you buy in October/November, chances are you won't be listing until January, anyways.If I had a house completed on, say, December 15th, I would likely sit on it through the holiday season before taking it to market, but I would talk to realtors.  

Now, pulling back the curtain a bit, if you act up front as have acted here a service provider will sense that and, intelligently add-on additional "WTF" charges because it's anticipated your going to burn up tons of there time in additional "WTF" items such as demanding to know how many minutes xyz took. 

What bed/bath count has the highest occupancy rate (occupancy rate will reveal demand for certain bed and bath counts in that market)3.

Understanding cap rates, net profit and economy (supply/demand housing, interest rates lowering increases demand, the real estate cycle, investing for cash flow vs appreciation) will all set him up for success.

I would recommend looking for places outside the major cities (at least Ottawa as right now it is crazy expensive, I'm not sure about the other cities you mentioned) and look for cities that are still growing but the demand is not super high.If you're set on one of those cities perhaps brrrr investing is the way to go.

Trades are in high demand and tough to manage

Zenda is a very small town so I question the demand for folks wanting to live there so that effects both flips and LTR and is a far enough distance from Geneva Lake that IDK the demand for STR so all of these things must be considered.