If the public record or a past sales shows the number of bedrooms/baths, square footage....  

There have been similar SFR within the area that did sell above $200K in the last 6 months and some with a smaller square footage. 

The realtor that showed me the property only found two properties, one with less square footage than the subject property and the other with different characteristics (the subject property is a 3/2 and the other comparable was a 3/1 with a 10% overage on square footage.

Yeah pretty easy get a SBA 504 loan in which you can finance 90% of the total acquisition cost and TI's, you bring in 10% down and must occupy 51% of leaseable square footage then do your numbers from there to see if that rental income can offset your monthly expenses.

As I understand it now, I cannot force as much value on the underground footage as I can on the above ground footage through improving the property condition...Anyone have experience with this?

I haven't seen a fire damage rehab, with similar square footage, that could be done the right way, for less than 40K,  so you are probably on track, depending on status of the HVAC.

Get info from the city like total building square footage and Owner information.

In a perfect world we would love to use homes with the exact same square footage, bedrooms, baths, architectural style, etc. but sometimes we have to make exceptions and make a decision.

All,Looking for a recommendation on Phoenix rehab contractor that can do estimates for fire damage, adding square footage and most importantly experience in pulling city permits in Phoenix.   

This house had plenty of room so it was not a big deal to give up the usable square footage for the new staircase.