I've used Odor-Xit with some success after a deep clean, and sealing with BIN primer, but this was on the subfloor, which I then installed new flooring over. 

On tenant flips there are ways to cover odors and ways to eliminate odors and sometimes both are required. 

We also discovered that it help the cat pee odor considerably.We couldn't spend any time at all in this house until we got these problems under control.Our plan was to kill the fleas first, then address the odor.

Odors!

-All carpet must be washed, free of stains, and no odor left-Locks must be in good repair and key's returned to the owner along with a forwarding address of where you are moving to.

Does it construe mixing of assets or anything that might foul up the operations of <address LLC>?    

Once that odor gets in, it's almost impossible to get out.As a side note, you should be careful with your language.

I know some of the smell could also be in the carpet and pad (which is being REPLACED), so should the concrete subfloor under the pad also get coated in the same odor-blocking primer?

I use this ozone generator and it works great.This machine can work really well on light odors without any heavy cleaning.

Even if the smoker doesn't smoke inside the unit, they will bring the odor in with them on their clothes.The cost to restore a 2 bedroom apartment after a smoker was greater than $2000.