They have no real estate experience and are just going off of general perception.The next big problem is that he is supposedly ordering a new HVAC with the A Coil and outside unit that he wants to install himself.

I also will get a new outdoor AC unit in the spring as the hail destroyed the coil on my old one. 

Just used a miter saw and trim nailer for the first time in the past couple weeks while working on my personal residence.  

The tenants don't change or clean their filters, the coils get dirty and we have to spend $150 to clean the coils.

Most homeowners usually find out once they have gotten sick or notices the coils on the AC have turned black.

In my specific case I was buying a HUD foreclosure and 2 days after I put it under contract someone stole all of the copper pipes and the HVAC coils.  

AC replacement around me is about $1600 for an A-coil and condenser unit installed.

He's recommending replacing the furnace with a new Lennox furnace and evaporator coil, for a total of $2287, 10 year parts and 3 years labor.Which would you select or would you get another technician out to re-diagnose the problem?

The kind with a coil wire, not the kind with a flat metal ribbon. 

The coils and 180 degree fittings are all fabricated from 10 foot pieces of standard black pipe,