I'm currently working on putting together an Excel file comprised of U.S.

The HVAC system is a unit of property and in your example, all 50 HVAC units plus the corresponding ductwork comprise the HVAC system as a whole.

We ourselves bring in simple items like hand towels, soap dispensers, fake flower vase, stools (when there is a breakfast bar), etc. even minor items can help make the property feel more "homey". 

I'd guess that inexperienced sponsors funded by inexperienced limited partners comprise a larger percentage of the failures than experienced sponsors funded by accredited investors.

Do the owners supply things like soaps, dishwasher, laundry detergent?

As I step off my soap box (sorry for getting so worked up), let me add that being an activist landlord in low income neighborhoods is the most profitable position to operate from.

Is dish soap really all I need to do?

This is an abbreviated soap opera: There's a house that I'm interested in purchasing; however, there are five interests in the property: 1/2 interest, 1/8, 1/8, 1/8, and 1/8.

Try washing a door with Murphy's oil soap and see if it look more "new", or "new enough" to re-use, and maybe think about just working with the cherry or whatever color the manufacturer put on.Also if the cabinets are not luxury to start with, the finish probably won't make them so, as because as others have said, they lack the special slow close drawers, dovetails, special cabinets, wine rack, moldings, etc... 

@Joe Gilroy, believe it or not, the surrounding submarkets of Atlanta have several neighborhoods that are comprised of 2-4 unit properties (mostly duplexes).