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.

I bought oil based primer, which helped to eliminate strong smoke odor.

We finally sealed all the walls, ceilings and floors with Zessner odor killing sealer which helped a lot, purchased an air purifier, and kept the house open as much as we could. 

Upon inspecting the house she found that all the upstairs flooring (carpet) would need to be replaced door to severe pet odor.

Regardless cats do stink no matter what you do and it takes time and effort to eliminate the odor. 

Here’s how odor is typically handled on a fire claim by an insurance company.- First option is just washing (degreaser etc.) and thermal fogging.

-Also got the bathroom tiles repaired, that was a bit of work as well-Had the initial floor sanding, that took out a lot of stains and odor, but still need some repair work done. - have now confirmed all the baseboards need to be replaced, the cat urine is down behind them-- another small bit of cash I was hoping not to spend.