If it’s a full gut, then it would behoove you to do a traditional forced air system. 

My experience is that people who buy these units do so at a considerable discount and basically have to wait for the tenant to die or break some kind of law such as subletting/Air BNB.Also rent controlled units generally have SIGNIFICANT deferred maintenance issues because there is no incentive to maintain them.

The banks probably has resources to prevent these scenarios. 

Between the inspection ($595), encapsulation paint and cleaning ($1,900), air duct vapor treatment ($700), and another inspection to receive certification ($250), I'm wondering if all of this was necessary. 

In the end my time was wasted and I prevented him from showing the property to other buyers since I had it under contract. 

In  1965 only 10% of homes in the USA had air conditioning, as this number has rapidly grown, people have begun migrating south due to the better climate.  

NOTE:  with the oil base primer, make sure whoever is applying has sufficient ventilation in place--I've seen plenty of painters get 'loopy' from the chemicals without proper air change ventilation.

The common advice seems to be, work at a fix before buying.Bring it to the seller in a tactful/reasonable way and just let them know that it’s a concern and I want to have it further evaluated prior to closing.I am hoping that they do not have a problem with it.Someone suggested threatening to walk and/or notifying bank of our suspicion and the fact that they will not let us inspect.I am trying to avoid any kind of antagonizing approach in the hopes that this can be resolved/mitigated without too much issue.I do like the property and not wanting to walk away, just want to figure out a way to resolve before I take ownership.For now, my summary action plan is to move forward with tactfully notifying the seller of my concern and desire to inspect, complete an inspection, mitigate or come up with a plan to mitigate and then also empower tenants to work with management at addressing mold by reporting any leaks in a timely manner to allow for prompt fix, as well as possibly suggesting they purchase damprid which I hear helps with moisture and making sure to pass on educational/informational material on indoor air quality.There is an indoor air quality guide that someone in a facebook group that I am part of suggested, which I intend to make as part of my lease addendums/guides for tenants.https://www.epa.gov/indoor-air-quality-iaqI do have a contractor lined up to address some regrading issues and also visible cracks which could be where the moisture is coming in through.The challenge is that mold is everywhere and I do not doubt, that we will find something, the key is to work together to “address/mitigate” vs. turning a blind eye which I suspect may have happened here.In the end, I like and appreciate all the comments.I think the comment that sums it up well is @ Clay Hartwig’s comment that the problem is not limited to just the tenants getting sick, the problem is also in working to mitigate moisture which could essentially kill the house.Thanks again to everyone that offered suggestions on what to do here.

I'm not sure about Kansas City, but there a lot of Air BnB's at the Lake of the Ozarks and in Branson. 

I would also add that you may not get out of the Transfer fee, I know in Pennsylvania that does not prevent you from paying transfer fees on the property, the property is still considered sold, not transferred with the LLC.