I know that the newer portion of the building is currently rented out to men that restore old cars and trucks.

There are several good manufacturers out there that make elastomeric acrylic coatings designed to restore metal roofs.

Like x number of $$$ per sq ft to restore an old and decrepit property to modernity.  

Landlordreserves the right to restore the landscaping to its initial condition, as itwas at the time Tenant began occupancy, or if improved during Tenant’s occupancy, to the level of such improvement. 

The interior needs a full restoration.

Are you just putting down the 20%  in cash and financing the rest, or are you paying all cash?

@Dawn Anastasi Do you have a Habitat Restore nearby?

We also had a neighbor have their two family status restored prior to purchase but it had to meet current code.

While your costs should not be as high as a new build, in your shoes, I'd probably budget at $60-$75 per sq. ft. depending on the amount of structural alteration and restoration involved and the level of finish you would be placing in the units.

@Brian Sorensen - Something to bear in mind is that there is a vast difference between a renovation of an old house and a restoration of a old house.Renovation is expensive.