I've never had a fire in a home so I truly can't say I understand how it damages the property, but I've had oven fires, and lots of wood-burning fireplaces, so I don't quite know if the smoke/ash is a big deal?

We only kept one wall, the rock wall with the fireplace on the left side of this picture.  

We got all the interior walls out except the ones attached to the fireplace.  

Though it may have been quite some time ago, there is little to no upkeep to the weatherization of this house, other than the working fire place and the option to run the Central Heat/Air full blast.

I'd definitely do something with the fireplace brick. 

And some sellers will always believe the inspector found a problem and can not be educated.I had a home with a gas fireplace and artificial log set. 

The other half say...things move across the mantle over the fireplace, pictures move across the room, water turns on on its own, locked doors are found wide open, lights turn on on their own, shadows of a person walking up the stairs when there is no person, etc.The last in there was 6 people. 

Also as part of your lease or an addendum to it, indicate what they are receiving as far as House keys, mail keys, pool key, remote, gate remote, fireplace key and any personal item you leave in the property - IE patio furniture, washer dryer, fridge.This way it is clear when they leave that it needs to be left behind. 

I recently fixed the fireplace and hired a plumber and thay was $2000.

There several in the "Fire Place" under the Resources tab at the top of the page.