I, like David, wonder if you're talking about a Home Inspector, City/County Building Inspector, or a Residential Appraiser.
Regardless of who made the recommendation, I'd get that roofing and mold specialist out there. Nevertheless, if a building inspector told you to do it, then you most likely won't be able to close without having hired those specialists. Similarly, if an appraiser told you to do it, then your lender won't lend to you without having seen evidence that you did hire those specialists. Additionally, some title companies won't issue title insurance for this property provided you don't follow that recommendation to hire those specialists.