@Ellen JesterWhile that is in the standard listing agreement, that is a clause with "no teeth" as there is no remedy for violating.  

They removed the decommissioned oil tank, and remediated the termite and mold found in the basement.

I would not consider repainting the entire unit as a solution in this situation, unless all other remedies failed first.

I am looking for remediation service to get the unit cleaned up.

Even if it were, it could be remedied quickly by regrading or installing a French drainhowever, it's important to ask these questions as a new investor 

The seller agreed to take it out and remediate the soil.

There is something "Off" with each property but based on our proposed uses and remedies are worth the cost of the land.  

For mold remediation (air quality test in livable areas came back acceptable), sump pump/french drain, vapor barrier and some jack post installation, it’s going to cost me between 12k-16k.

Would treating the homeowner as an investor remedy the Equity Skimming/Fraud concern?

I have noticed that guests will tell me of some minor issues, but do not want someone to come during their stay to take care of it, but I truly appreciate it when they let me know of any concerns, so I can remedy the issue as soon as possible.