Usually that 'special deal' is marketing smoke and mirrors (I can do a loan for anyone otherwise basically qualified with 3% down and no PMI, but there will certainly be a "gotcha," etc, regardless of if you have M.D. after your name - but that's not good marketing copy is it?)

The other side of the duplex has some minor issues of conduct, but I can handle those with a few property amendments (like adding a fenced in place to smoke outside and more garbage cans for the whole building) and a brief conversation.

If it says you cannot smoke, don’t ever let them smoke.  

The obvious things like smoke detectors and stairwell handrails are to be fixed, if any issues exist.

Same concept as smoke and CO detectors.

Like @Marcus Auerbach said, do a review on HVAC and roof, gutters, double check plumbing/drainage, and make sure filters, light bulbs, and smoke detector batteries are all in good working order.Do a walk-through of the property as if you were someone looking for a place to rent with a hypercritical eye.

The vent on the wall is simply to get some of the heat (and smoke) out; it's not required but that closet may get hot and damaged clothes (or not...).   

The title is on my name.The tenant pays rent on time but is extremely filthy, argues a lot, smokes inside, has a pet that is not trained properly.On 5/29, I texted him that I do not want to renew the lease and told him to move out on 6/30?

I have not yet received said email but they are smoking crack if they think I'm going to agree to any 24+ hour period between guests.  

Ozone machine for smoke or other odors.2.