My daughter just bought a house in St Louis, and it was inspected, and a year later, the basement smells like rotting mold.

You will have extra plumber calls due to smells and backed up toilets and the cost of the toilets.

We used an ozone generator to eliminate smells.  

Has anyone charged a smokers deposit so if the apartment then does smell like smoke can use to help rectify.  

You don't have any proof that she has moved another person in, and just because you smelled them smoking doesn't mean that would hold up in court.

However, I'm not sure if the seller's submitted contract will allow me to do so, although there is nothing within the body of the contract itself that mentions anything binding me from doing so and my seller is absolutely fine with the idea of me assigning my interest elsewhere.

I've talked to my title person, county assessor, real estate attorney, and any body else I think may know what to do, and no one has been able to give me any advice that I can act on.

My real estate agent in the area went by and took some video and described it as "creepy and old," the tenants had smoked so the smell was awful, and the neighborhood was "hood" - she didn't really feel safe there just taking a look. 

I think there's a way for both of you to come out smelling like roses.  

Have any body had any experience with this?