How much of a concern is it to not be able to rebuild ? 

You can do some preliminary homework yourself by contacting the local zoning office (whoever governs zoning in the Subject area) and ask them what the policy is on rebuilding a damaged nonconforming structure.

Without knowing more about the property and it's condition, I can share that my clients have done complete 'rebuilds' of properties in St.

The next one after this is a complete demolition and rebuild.

We are trying to rebuild we're about 60% done and the mortgage company will not release the insurance money to pay the builder because the builder won't sign a release of lien.

I have one in the North End, it's absolutely up and coming, 5 rehabs in my street, unfortunately most houses on the market are total gut jobs and they're starting at 25k+ (depending on the size of the house) and you basically have to rebuild the house.

But when my architect did Point calculation for Santa Clara permit purposes, it comes to be 77. ( seems all walls that needs to be added / removed ) add up costing these points.He mentioned anything above 55 points is not considered remodel instead rebuild, which has a long/different permit process.

The biggest ticket items were the demo/ rebuild of the back end of the house & re-pouring the patio ($6k), the HVAC system (ductless mini-splits $8k), drywall & paint ($4k with materials included), and the spray foam insulation which I did on the roof and exterior walls of the building ($2,900).

I would guess worst case you are looking 15k or so on interior remediation after demo and before rebuild, but that is just a rough guess. 

-OR- Detroit is where you land if you want to make a name for yourself as an investor in one of the many emerging neighborhoods and want to be part of the energy of rebuilding one of America's greatest cities.