So I have 2 groups of general contractors (each has around 3-4 daily workers), 2 roofing companies (both very reasonably priced and will ALWAYS return my call), an electrician, an HVAC tech, a painter, and a landscaper/masonry guy who I consistently work with.

I’d contact William McDonough or Arch Masonry.

Go silly with spray foam insulation down there, wherever wood meets stone/masonry along your exterior walls, and especailly on those gaps around both of the doors.

My main business is masonry restoration but I am also an real estate investor.

I currently work and have worked construction for the past ten doing tile, perfect granite countertops and other masonry like brick, and natural stone. 

Masonry work can be $$$$.  

So I will present that to the seller along with the estimate I receive from the masonry on Monday to re-point all bricks including a second coat over the brick completely and pour a new slab on the basement floor.

One building is a two-story, masonry bottom, frame top 4 unit apartment complex.

Code will very likely call for a masonry chimney to be re-lined and a metal chimney to be replaced.

Unfortunately, outside of rural/exurban areas, the majority of our older housing stock is quite large masonry city rowhouses that are really only workable as multi-unit condo conversions due to the heated up market.