I have a fairly long stretch of rigid metal ductwork in he crawl space of an mid-50-ies property.

From my understanding that is the best way to retrofit central air due to the lack large duct work.  

The way it's laid out up there now, there's a lot of unused space that could be allocated to the second bedroom.The HVAC contractor was going to stop by today to get the plans for the new furnace and ductwork, but he's delayed until Monday! 

If you are not a smoker and your other tenants are not smokers then it can be a big problem.If you get this lady to leave plan on de-greasing the ceilings, walls, ductwork etc. to get the film of smoke out.Either way it sounds like you are going to be spending a lot of money in the future so plan for it now.

IMO i'm providing plenty of outlets for them to use)4) There needs to be a copper or galvanized steel pressure relief valve blow off pipe on the water heater. 5) The drywall on the ceiling in the utility closet around the duct work for the furnace needs to be repaired. 6) Wasp nest outside back of house in the left corner needs to be taken care of. 7) Check to see if a back flow preventer is built into the hose in the back of the house?

New carpet, new sheetrock, new paint, and clean ductwork.

We will re-pipe flute pipe, electrical, refrigeration piping, install Aprilaire media filters and add grille with duct work through the wall into the finished area of the basement.

You may have to remove some anyway though, if for example there aren't enough receptacles or there's no insulation or ductwork, etc.  

We had a dehumidifier running 24/7 & its proved to be a simple cost effective solution using old ducting & an old ductwork fan.

The units are equipped with central heat and air with duct work but only about 6 are in use.