She would get drunk, makes a lot of noises, smokes indoor and claimed that she lives in the building.

You're right - in your scenario the seller would have to be smoking something or dumb.  

Checking smoke  and carbon monoxide detectors annually which is owner responsibility in this state?

.- The re-inspection fee, if needed, is typically in my area the result of a listing agent not doing their jobs and double strapping the hot water heater, putting CO detectors in, or otherwise ensuring the property is in financeable condition on the day it is put on the MLS, with no blatant health/safety issues, etc etc.

Currently rented to long term tenants of 4 and 8 years (both smoke and are pretty messy) paying 700 and 750/mn.

As you'll see below from the photos, the damage was pretty severe - including smoke and water damage as well.

If you do not want smoking in your unit you can not rent to anyone that smokes.

Our application asks whether they smoke and if they have any animals (do not use the word pets). 

The last expensive turn I had (tenant left it a huge mess and smoked inside etc), I used a painter, a landscaper, a plumber, a cabinet counter refinisher, cleaners. 

They are in effect using smoke and mirrors to inflate their returnes.Alternatly The DP should be assigned a 10% return as it's opportunity value.