Job included inside work of leveling floors, installing flooring, paint walls, kitchen cabinets, etc in both units, as well as lay a new driveway, fence the back yard, provide attic fans, and install electric to the crawlspace to add lights and a sump pump.

The only way they would seriously consider a higher offer from an unqualified buyer is if they have no offers from better qualified buyers and their back is against a wall. 

I'd personally say pulling your water heater out and replacing with a wall mount on demand one, would be worth the cost to have in unit washer dryer if you are staying there or renting it, it would be worth it.its always worth doing the big stuff well and correct even if you are cleaning up after someone, the long term hold always prevails, its just a little frustrating front sometimes, but hang in there!

Also, many PadSplit properties have bedrooms that are created via flex walls that wouldn't meet the definition of a bedroom in an appraisal, so many PadSplit owners may think their property is worth a certain a mount based on a bed count that's not valid. 

It’s a 2/1 750 sf house built in the 1920s with  a concrete wall foundation and partial basement.   

Why would you want to keep it "behind the walls"?

@Diana Teng there are a LOT of potential pitfalls:(So, it's vitaly important to not just find someone that you think you can trust because they tell you what you want to hear, but you find someone that their processes seem a good fit for what you want.EXAMPLE: we do BRRR Turnkeys for clients and take numerous vides we share with them - initial, worst state of any demo, when HVAC, plumbing, electrical update BEFORE walled in, before any major payouts and of course a final walk-thru video.One thing that's accurate from all the HGTV renovation/flip shows is that you should expect and plan for surprises!

Windows would be my next check-point (less than R1) and then wall insulation: I would not be surprised if they have no insulation inside, but you can do blow-in, which only requires a small hole.A home looses heat in two ways: heat conduction (which you can slow down with insulation) and drafts, which in old houses is usually the biggest culprit.

Kitchen cabinet handles were placed upside down, cabinet doors were installed backwards, electrical line for thermostat was ran on the inside of the bedroom exposed, trash swept into newly installs vents from the furnace, cracked tub, wall switches were installed sideways in some rooms, wall outlets were installed upside down on some walls, list goes on.

I sold the other Class C while it was vacant - I saw the writing on the wall so decided to cut my losses.