YUP its a non contact sport out in C class rental areas and some B class .. one thing to tip U off when your looking at rentals drive up and down the streets and take note to how many condensers have cages around them.. then you will know that if you don't cage yours good chance its stolen and will get stolen many times over the years.. 

Assuming I need a new condenser, what is a reasonable price for a 2.5T or 3T unit installed in Nassau county NY (near JFK, so not that close to Manhattan, but not that far).

I’ve since asked for further clarification but I have two major concerns. 1.) the 2 ton HVAC condensing unit is inoperable. 2.) their is a 100 amp sub panel only being supplied with 50 amps.

Called the company office this AM and was told that a breaker was replaced in attic and then the condenser motor was replaced.

Normally these are meant to slope towards the outside a little bit, so condensation will head for the outside.  

If you install a new furnace, and opt to not install a new evaporator coil and condensing unit, you will pay almost double in labor, as the company will have to disconnect all of the furnace attached duct work, to install a new evaporator coil, as well as evacuate and vacuum the system down, a second time, when you decide to install the new outdoor section. 

They make systems with multiple indoor units connected to one outdoor condenser. 

I send over my handyman and he discovers that a window unit(non authorized) leaked condensation back into the sub floor and has caused about 500-600SF of sub floor and flooring damage. 

That may have been true for some older mini-split systems where one condenser served multiple heads but modern heat pumps don't use resistance and are usually rated down to -13F (though again, I've seen them pull heat out of -25F air very nicely).

The fix for that is usually shutting off the power at the box on the side of the house where the cable from the A/C connects, hosing it out with a garden hose (use a wide spray nozzle rather than a thin "laser beam" of water, so you don't bend up the fins on the condenser), letting it dry out for a couple of hours, and then turning the power back on.