(Have a furnace in basement currently for heat, does this make the central AC installation easier/cheaper?)

Prime GeniusRhino Heating & AirJaguar Heating & AirThis is just a few I can think of off the top of my head.

And replacing all appliances- Renovate the bathroom with new tiling, etc as neededEntire house needs (not urgent besides the windows + meters/heating):- Replace concrete panel siding and brick veneer- Replace railings on the front balcony and stairs- Bigger project: Convert the ground floor garage into a living space for the first unit (who should I contact for help with this?)

.)- Condition of house and property (have the systems such as Roof, Plumbing, Heating, Electrical been updated) - claims history of the property- age of the buildingI would suggest seeking out an independent agent that can quote multiple markets.  

They were unable to use the stove or the heat in the apartment for about 2 weeks.

Violations of code, like not having GFCI outlets on plug ins near the sinks, tubs or showers, not having licensed professionals do work on electrical, plumbing or heating. 

Can save you from buying a deal like this OR be a great negotiation tactic.Yes, every time....I would still contact the seller and put some heat on them....you never know what might happen.

Heat pumps that allow for AC yada yada  If the electric is already separated would an improvement lower the tenants costs and therefore allow you a better rent.Low flow toilets, shower heads etc.

Do you have a boiler or forced air heat?

If they leave during the winter holidays they are not to turn their heat off (as some like to do to save $$) or the cost of repairing frozen pipes will be on them when they return.