Weed smokers aren't going to stop smoking weed because you or a lease says no smoking. 

I don't rent to smokers.

Not as clear to me is how to start this process in multi-family properties where smokers are already in place.

My guess would also be, if the neighborhood is anything like what I understand about the frogtown area, more residents are going to own a dog.P.S. you may want to consider offering a month to month lease with 60 day move out notice, or lease until the end of May - August.One more thing: I would not eliminate smokers.

Talk to all previous landlords, not just the most recent.Avoid smokers.... they are not a protected class and can do a lot of damage to your property.

Half of the rentals that I walked through had the alarm sans-battery because the idiot tenant needed a TV remote more than a smoke alarm (usually these are smokers, too).

Convicted felons and smokers both fall into the same category of not being a protected class correct? 

Some behavior you want to exclude right off the bat for sure - smokers, etc - and I don't disagree with your premise that I don't think I'd want that situation under my own roof - but if a person is not breaking any law, you have to either let them do what they want within reason or let them seek accomodations elsewhere.

Decide what you're willing to compromise on-- renting to pets, smokers, students, bad credit, or what?

Right, I'm referring to minimum credit score, 3x monthly rent income requirement, non smoker.