I just hope people are estimating accurately. 

But yes, as with any endeavor, you need to do a thorough analysis and accurately account for all expenses.

when he could of taken the same time to check the city's website for an accurate assessment of the property.

Sadly, that's where I learned the hard way that even with the best planning, accurate projections, and all the right things in place, events beyond our control can still come into play (9/11 in my case).  

I need the names of the occupants, and am curious what would be the most accurate and cost effective way of finding them.  

@John Zoulis I wouldn't trust 100/sf, you might ask a local builder to determine real and accurate prices, 150 and 200/sf is a safe number, for analysis, use those numbers, many can do it at 150, but your GC choices will be limited, use 200/sf just in case you run into problems or not have enough experience.

I don't want to demand more than I should, but I don't see how I can make accurate decisions with so little information.

Certainly you have to accurately understand what it takes to repair and do work… I was curious how you start at all.

Is this accurate?

Then do that with a couple more contractors to ensure you're getting some accurate information.