I'd put in thicker sheathing plywood and do a thick luxury vinyl plank floor.

A coat of paint can do wonders for changing the appearance.Remember when changing out cabinets and flooring, you want something durable and that will appeal to a lot of people. 

We must have used 5 coats of primer.

Well, no offense, but for 5 inches of snow we may not even break out the winter boots and coat.

Those nicotine vape pens exclude an oily substance that coats everything.

To repair the drywall then paint ,I think the $750 is on the cheaper side .  1 trip to look at it , 1 trip to pick up materials and repair and 1st coat of mud , 1 trip for second coat of mud , and 1 trip to sand and paint the entire ceiling .  

Then I'd get a quick coat of primer on the walls to cover all of the nasty look and gut the kitchen.

I had to have the duct work cleaned, (no carpet, but would of torn it out), scrubbed the entire unit top to bottom, painted every paintable surface (walls, ceiling, and kitchen cabinets) with the oil based kilz with two or three coats.  

Also a new coat of paint or swapping out the door handles for modern ones can make a big difference.

Hopefully you will find metal jacketed cable that holds the copper within it, and the copper will be coated with a rubber/plastic, and not cloth and tar.