I can't speak to that myself, it's not my specialty but I think that would be one of your biggest concerns is their permit processes. 

Definitely recommend reaching out to the city first to confirm what permitting would be needed for added square footage.

Since most of the homes that flooded took on electrical damage, you will almost certainly need to file a permit to do renovation as you will need the electric company to shut the power off, provide temporary meters, and turn the power back on.

After  3.5 years we have permits for a 17 unit redevelopment project.We had hopes that we would break ground within a year of buying the property....that fell by the wayside for 2 reasons:1) we had worked with the city to increase density through an affordable housing scheme that did not go as planned.

If there are only 2-3, then investigate and question GC.3) Check with your state's Attorney General's office for any complaints.4) Contact several City Building Depts in the area and ask for list of permits they've pulled.

Working thru permitting.  

If there are any known issues(even as simple as a bad $7 shutoff valve) you will not be permitted to turn on utilities. 

I'm a civil engineer, and for example, I do the civil engineering/permitting for many Gas-Station & Convenience Store.

I know one-sided relationships usually don't last, but given my lack of experience I doubt I can be much of a value-add friend - unless you're looking for insider tips on how NOT to do some things :)  So you folks with more experience, let me know what kinds of things turn you up or down when it comes to newcomers.

I am intrigued though and will be checking more out as my time permits.