Today (at least in WA state) every law you can think of has been written against you, and you'd better know them or you'll be in hot water fast. 

If there is smoke or water damage contact a restoration contactor (I've had clients use Belfor and they were pleased with their service (do not sign a contact with any restoration company without the ok of the Insurance adjuster.  

This affords the opportunity for a homeowner to sell the property if it is not under water for market value and pay off the loan before they are foreclosed upon, or more commonly, short sale the property with the bank's approval. 

Your costs you might not think of are insurance, water, sewer.

Even if we did tear down and rebuild, im afraid it would put us under water or at a break even point if we are super strict with the build budget- plus adding to that, I don't know how the rehab lender would even look at this now if we do have to tear down.

The roof and the floors were not huge costs to us the buyer, as the seller filed an insurance claim for water damage just prior to our offer closing.

Here I'm thinking it'll be easier because there was literally a house there before and there's already electric, sewer, water and gas at the street to connect to. 

He didn't have time to come out for 2 weeks but said high consumption is almost always the HVAC or water heater. 

Is it common place to call the utility companies to get information on electric, gas, water and garbage pick up?

strictly read, the city of Austin requires a permit to spray foam insulate around an outdoor water hose bib...because it improves or repairs a structure.