I don't know how thrilled you will be with this, but to cure your smoke odor, before the carpets are clean, prime all the walls with waterborne or solvent based blocking primer (Kilz, Zinzer or equivalent) and repaint. Watebornes are not nearly as nasty as the solvent based stuff, but they don't block back stains as well if you have to stop stains from bleeding through. That smoke and nicotene has been absorbed into the surface of the current paint and you cannot scrub it out. It will stink forever if you don't bury it. And as you know, people coming in to rent that place will notice it immediately if they are not smokers.

Good Luck.