If you don't mind spending a few dollars, you can get your/a lawyer to send her a "cease and desist" letter regarding her behavior, which may or may not be effective but at least lets her know you mean business and aren't going to put up with her BS anymore. 

We even installed additional insulation and a vapor barrier to prevent further moisture damage. 

Alternatively he suggested adding dirt to level out the space and then installing vapor barrier for $800.Anybody had experience with this before?  

Initially, I was concerned but seeing that your PM managed to get a co-signer on this contract speaks well for him / her. Being

From there we led the water out of the crawler, then we put a nice thick vapor barrier throughout the entire crawler and sealed it.

Revisit the comps and valuation, your ability to buy and I'd suggest you simply lease it if you do anything with her, being unemployed that's hard enough to justify.

I see the tile in the basement unit, is that installed on the slab or against a good vapor barrier? 

These rolls can be purchased in various densities to accomplish higher R-Values, even for cavities of the same thickness.As for what's best or most efficient - questions without absolute answers in my opinion... find out what the pros do in your area - that'll be a good indicator.Also, given your locale, you may be required to have a vapor barrier, so be sure to check into that.Good luck!

We decided to have a vapor barrier installed along with a sump pump in this area which cost about $4600.  

"Risk something or forever sit with your dreams" - Herb Brooks