It was too dark. 

Just a shot in the dark here,  but I thing AirBnB, VBRO et all are aimed at short term rentals BY THE OWNER, not to used as a business model.  

There are some issues working with houses that suffer from burnt materials and smoke damage.The one I did was an auction house.

This is a good way to buy distressed property, once you buy the property, remove all burnt walls and damaged areas (in some cases must take it down to the studs) and use a "Ozone Generator" to remove the smoke smell.  

Without talking to one, you'll always be in the dark and could worsen the situation by taking a wrong step. 

Quick shot in the dark to anyone with more experience than I do!

They see a rent amount per month and then they call (gets awkward for them when I ask them if they smoke because in the HEADLINE of the ad it says no smokers.....and they go..."

Systems include HVAC, plumbing, electrical, roof, foundation, windows, etc.Health and Safety - RequiredIt is important to provide a safe environment, which includes items such as smoke detectors, transition strips, trip hazard removal, lock rekeying, and more to ensure a safe environment.Items Necessary to Attract Your Target Tenant Segment - RequiredIf you want to attract a specific tenant segment to occupy your property, it has to match their housing requirements.

You may also want them to fill out an application to be sure they can afford the higher rate, you may also want to offer them a written lease with your terms (like no pets, no smoking etc) or other terms and conditions.So I guess what you might want to do is concentrate on the unit you want, get that vacant and in the meantime just keep going with the other unit.

There are misting products out there that claim to neutralize smoke/pet odors chemically but I haven’t tried and yet.