I had a friend that was at the point of tiling his new shower and putting up kitchen backsplash when the inspector knocked on the door to snoop around.  

His office specializes in Section 8 and has a relationship with most of the caseworkers and inspectors in my city.

Then one day, an inspector from a state agency showed up, asked me for all types of records.

I also have a Rolodex of reputable industry contacts including, closing attorneys, general contractors, inspectors, etc.I would love to set up a time to meet and chat about your goals and develop a plan of action!

The inspector is correct that you should have a chimney lined.

If you are going to have a PM to run it, agent's to run the transaction, inspectors to run the inspections, what does being boot's on the ground do?

But they also take a "buyer/renter beware" stance and their view, based on my interactions with building department and section 8 inspectors is: as long as the house does not have cracking or chipped paint, the chances of it effecting people is basically non-existent.  

If this property is already under contract, then be sure to hire a high quality inspector to get this information for you. 

We've reached out to propery managers, inspectors, and even locals on reddit to get their second opinions of the invisible barriers to the neighborhoods around it. 

It seems the previous owner did some patchy repairs to cover a leak, which might have been harder to notice, but the vent not being there should have been something the inspector picked up on, at least to mention it to you.