They intend to rehab/rebuild all of them to the same standard.

If it’s “destroyed” the city/county/state is going to make you scrape the lot clean if you don’t plan to rebuild. 

An insurance company will probably put a rebuild cost of $35 per square foot...so if your facility is in the 15000-20000 square foot range, I think your quote is not out of whack. 

I’m rehabbing a home now with foundation issues and rebuilding 3/4 of that with block wall is $12,500.

We will want to basically totally demo then rebuild.

This can incentivize a tenant who had a bad situation to help them selves by paying you rent to rebuild credit.

In a Northern VA market where so many old properties are marked for tear down and rebuild, (1) how can I go about convincing the seller to lower the listing price so the math supports the renovation? 

Make sure you get insurance for the cash value of the property rather than the much more expensive re-build value.

If you are in the south end do you really want to drive to Duvall to rebuild a leaky toilet?

I'm looking for a contractor to do a repair that might last a couple of years before I take the step of demolishing the whole structure (and probably rebuilding).