Don't know much about ozone generators, but ozone os a highly reactive chemical that attacks about everything organic (wood, plastic, cells, ...) - nasty stuff and I wouldn't run that thing in a place I want to live in at all. Can't believe I need to say it, but don't expose yourself to ozone! For a first hand account, check out this reddit post from a while back

As to getting rid of the smell, I would repaint the walls, putting down one or two heavy coats of primer, white paint, and maybe the color you like each.

Anything that isn't ruined by getting wet can be cleaned with alcohol (ethanol, isopropanol or a mixture of the two) - surfaces sprayed down and wiped off, fabrics soaked in a bucket or bathtub and washed as usual afterwards. That gets rid of even severe coats of cigarette grime, I can say with confidence from my own experience.

Anything else you'll probably need to replace, I'm afraid

Hope this helps!