Once you've worked with your contractor long enough and have seen his estimates play out  - you will have a better idea of how close he is to the mark - many contractors will low ball you just to get the job - then once he is knee deep in it - more expenses suddenly rear their ugly head ...this happens to all contractors - but the good ones will have accounted for the unknowns up front and should come in close to his bid unless something major has been discovered -  best of luck to you - let me know if I can connect you with anyone

This keeps tenants from not paying and running up an unknown bill on you.

But, here's some more detail - . we're using a licensed roofer. 1 story, ranch but with a steeper than usual  roof for a ranch.  . removal of the existing shingles and torch on (improper use). not including the sheathing/fascia/dry rot cost bc it's unknown how much if any will need replacement. 

It would also depend on my debt or equity.I would never figure on future appreciation because the future is unknown.  

At the end of the day, it will always cost more to protect yourself against unknown people, even if you live in the same building. 

Though this is my 2nd deal, this represents a red flag (unknown as to what is in there and it's condition, the home is 110 years old) to me and among other smaller issues related to water stains in the unfinished basement (satisfactory) non working sump pump (can be replaced), water heater leaking (agent said will be replaced) , etc .. how should I approach this???

I had a couple of nuts that I had salvaged from scrap kitchen faucets of unknown brands, and they didn't fit either.

You could get 100 different suggestions here and none of them would work because of unknown conditions and specific circumstances that surround your house. 

Question that is unknown is what will happen to prices.

File a claim in the bankruptcy case for the utilities, and for unknown amounts for damage, unpaid rent, etc.