I would Consider hiring a Mold Specialist for a Moisture Inspection and Mold Assessment. In my experience, usually Mold is a result of moisture. This could raise a flag on other issues of latent moisture intrusion.
I was a home inspector in another life specializing in Mold assessments.
I am not sure what the requirements are in IL, But in some states there are requirements. If you hired a home inspector maybe he can recommend someone licensed or Certified by AIAQA.
This may help you make an informed decision before you just jump in or possibly turn away a great deal...
AIAQA >>
www.iaqcouncil.org