This deal above for example; the initial conversation was basically a dead but following sealed the deal.Thanks for the reply hopefully people will understand it takes work and a little magic.

A hammer can club endangered baby seals, or it can be used to build something great, it depends on who it is given to and how they use it.

We then had to put two coats of Kilz on the ceilings and walls to seal it all in.

If you have made any effort to reasonable air seal the building envelope, then you need the range hood to extract stale air and humidity as a regular air exchanger will not typically be able to adapt to accommodate cooking.Even if your house is not tight, it is still appropriate to properly vent the cook top to prevent moisture damage and grease build-up on the ceiling above.

Virtually all of the homes impacted by this event were substantially above seal level. 

I have some low end rentals I was debating on using this and sealing it with a waterproof sealer.

Now my greatest challenge is to "Seal the Deal".

Do the doors open and close, allowing access to the rooms and sealing out strangers and the weather?

This, in effect, would weed out the bad apples and the ones who don't have the experience and knowledge to understand how to make offers, seal up a deal and close.

Here is what I used with the 10 year battery. https://www.homedepot.com/p/Kidde-10-Year-Sealed-Battery-Smoke-Detector-with-Photoelectric-Sensor-21027434/203525026I think they offer a slight discount for multi-pack order but they are basically $20 each.