Cigarette smoke damage - suggestions

To the Eichler community,
I’m familiar with Eichlers because I’ve lived in Palo Alto and the San Fernando Valley. We’ve just moved to be faculty at the University of Minnesota. We bought a house that is Eichler-like. You can read about the community below. We have a lot of luaun plywood wall paneling. We bought a house from a family of a chain smoker who died of COPD in the house, and the local realtor and family hid the news. They painted directly over the drywall, rather than remediating, which can create very toxic third-hand smoke. I can’t believe this is legal. Maybe you have thoughts about it. See links below. I’ve included a link to the house below (we think it's handsome).
We’ve done Biosweep, then Kilz restoration primer, and two coats of paint for the drywall. What to do about the luaun is the main concern. I’ve heard lots of suggestions.
1.     Replace or just wipe down with Murphy’s oil soap or Bona PowerPlus Wood Surface Deep Cleaner Spray. Does anyone have a preference? For the room with the fireplace, perhaps it's best to replace the luaun (chipped and watermarks), but I don't know a seller.
2.     Clean with vinegar and water and then scuff up with 220 grit sand paper, and then paint over with a shellac like Zinsser Bulls Eye Shellac. For the kitchen, oil based, Kilz clear primer and a clear enamel.
3.  I’ve read and heard so much about varnish and lacquer, also mixtures that have low VOCs. I’m leaning toward shellac because it’s handsome and will seal in the smoke, but everyone seems to have a different idea. Thoughts?
https://thirdhandsmoke.org/
https://no-smoke.org/smokefree-threats/thirdhand-smoke/
https://tobacco.ucsf.edu/california-thirdhand-smoke-research-consortium
https://tours.spacecrafting.com/n-pygsjk
http://ugrove.umn.edu/