She claimed "air quality" and "water quality" problems among her chief concerns.

Just make sure to check their credentials and experience, and find someone who can explain things in simple terms.Also, keep an eye out for any red flags, like promises of huge refunds without a thorough review or pressure to pay a percentage of your refund.

Peer pressure from their friends works 1000x better than anything we say to them. 

Together the portfolio is worth 2.5 Million and he STRs them on Vrbo and Air BnB. 

The air conditioning doesn’t work, the fridge is broken, and the property is far from "turnkey."

I would say air on the side of caution.  

@Sean Anthony to us, this situation is really no different than a nonpaying tenant.We try to work with tenants, as "life happens", while keeping pressure on them by moving forward with the eviction process.

They built a pole barn structure, air conditioned it, strung up some lights and trendy decor and host baby showers or weddings almost every weekend. 

There are several STR's on AiR B&B that do not abide this; are they likely operating outside of permits or does the county make exceptions?

They have stepped in to cover repairs for me, pressured mngt to do the same, introduced me to other PM teams that would perform better, shared multiple resources with me to assist with the sale of the properties and have spent ample time helping me strategize overall about what to do with these properties.