It has created a weird/hostile like dynamic between smokers and non-smokers who live on site, however.

Smokers are not a protected class.

One unit has a family with smokers, the other family seems to be voluntarily-smoke free. 

As for the smoker use the same cleaning solution on the carpets wash the walls down with tsp you may have to replace the curtains but that smell is easier to get out than what you've been dealing with. 

Start negotiating.Smokers can't smell their own smoke as well as non-smokers can.

Whether or not you have a car, it's great when you don't show up when you say you are going to.We love smokers, but we especially love it when you throw your cigarette butts everywhere.

Big negative for the house is that the current owner, a retired gentleman who is a smoker, has therefore made it smell like an ash tray (was painted in the last few years, so no terrible stains) and therefore will get rid of carpet and replace with laminate, and seal and paint throughout.

All I did was send a text saying it wasn't acceptable (especially because on the application they said they were non-smokers).

Major systems (roof, HVAC, foundation, plumbing) are in good shape, but the former owner was a smoker.  

I'm a little on the side of the smoker even though I don't smoke myself.