After tenant constantly refused to pay her part of the rent, only $14 a month.While smoking a cigarette..."

The tenants who live in the unit next to mine complained of an odor that smells like stale cigarette smoke in their apartment.

Easiest check is pour some Gatorade into the tank when you’re doing spring or fall smoker alarm pokes. 15 min later if there’s colour in the bowl you need a flapper.

The brick patio was laid by hand by an awesome guy I found on Craigslist who did all the work by himself, by hand, cigarette in mouth, flip flops and a giant jug of sun tea (again phx people, I would love to share his number, send me a message).

As far as smoking is concerned, you could always just keep the unit as a "Smoker Friendly" unit.

STRs only recently got a bad rap because of excessive use of police resources (kicking out smokers, parties, etc.) and now require fees and a license. - Back to your 2-3-4 unit dilemma.

I accept everyone except smokers because it’s not a protected class.

A poster here already mentioned about the stuff people waste their money on: booze, cigarettes, lottery tickets. 

Did he have money for his car alcohol cigarettes Netflix cellphone .

Smokers are not a protected class, stating no pets doesn't discriminate against anyone and requiring adequate salary to pay the rent isn't a problem either as far as I know since it is not a section 8 property.