Seems that the new tenants may just be really sensitive to the air in the house.

Texas in general is a large economy, i believe Texas has one of the largest air turbine farms in the country. 

The lender I work for uses that in addition to  an Air DNA Report and a reservation detail history. 

I would be happy to help find a good deal and get property set up for air bnb

No provision for forced air, or air conditioning at all. 

Some people are all about 'heads in beds' so they will tell you to pack every square inch of the house with sofa beds and air mattresses and cram the people in there.

When I look at air bnb at the potential areas I’m going to invest in, and the nightly average, compared to how many booking days over 4 months- seem to break even/substantially profit.

I'd also wait a few days after their quarantine is over and make sure there is good air flow and you have a N95 mask on when you do go in.

Now you might get an ROI on a ceiling fan if you need to push some warm air down in the winter from a vaulted ceiling! 

I would also check with Air BNB laws if you go the multifamily route. you might be able to earn more air bnb'ing out the additional units rather than a traditional yearly lease.