Did he or your hired gun inspector walk the roof, or fly it with a camera drone (???)

Try Hommati.com I've used Jonathan Duncan and he takes excellent pics, drone shots, videos, etc

Cat dander lasts longer than dog dander as it's more airborne."

Mold is everywhere and airborne but your inside levels should never be greater than the outside which indicates a problem.

*Once acquired, I hired a drone photographer to take pics of the property.

We got airborne a few times while 4 wheeling. 

From the drone footage on the GRM web page it looks like development has (at best) just started, and this appears to be consistent with the single page development activity status report from GRM.

Here's an article on the subject: https://www.washingtonpost.com/lifestyle/home/considering-having-your-air-ducts-cleaned-think-again/2019/01/28/cb5c14b4-1393-11e9-b6ad-9cfd62dbb0a8_story.htmlThe article is probably correct that dust trapped in ductwork is unlikely to become airborne.

Drone?

We just sold two old farm houses, near downtown, for $330,000, to a builder in less than 24hours after we listed with an agent who took drone pictures of the actual situation they were in and approximate to.