They didn't leave their units super clean always, but they did haul everything out of the units, and left without causing any damage.  

Just because someone supposedly owns hundreds of properties, doesn't mean it's lucrative or lucrative for the long haul, etc.Do what works and makes sense to you.  

They had rugs, toys or furniture covering up every stain.

Cel phone was a expensive toy, 286 computer just showed up in the computer store & fax machine was a big thing & every agents carried a pager.The day I get my license, I had been working in my own restaurant for 10 years.

As a lawyer, I listen to my clients goals, their tolerance for having to follow formalities, what is the source of $$, how they want to file taxes, the number of people involved, if they want to be able to get out easily, how the company is going to function daily, as well as over the long haul... and a bunch of other factors, then we discuss which entity makes the most sense for their situation.

You can haul the old appliances to the dump.

It will cost quite a bit to clean up (haul out old trailers (3K to 6K per trailer) + some additional legal consultation costs I imagine) then redo systems.

I would fix up the basement regardless (they are, and will be, non conforming bedrooms, because of no egress windows), just toying with the idea of taking a risk and adding a kitchen for and extra $7500 (its a strong rental area). 

Other ideas I can think of are; - perhaps an owl box - perhaps haul gravel for a driveway on the other side of the house

it was the landlord you spoke to?