Situation:
Development Company is presented by a broker with a project involving
the acquisition of a well located building built in 1937, with
antiquated systems and an unimpressive lobby.  The building is
substantially smaller than is permitted under current zoning, is fully
tenanted, and is owned by a third generation of the John Doe family. 
All of the present leases contain “demolition clauses” that require
the tenants to vacate if the building is to be demolished.  A large
firm is anxious to consolidate its scattered operations from several
locations into a new state of the art building and would be wiling to
lease a major part of the new building.

The Doe family has not decided whether to sell th e property to
Development CO., or to enter into a long term ground lease, which will
require the demolition of the existing building and the construction
of the new building.  Development CO. is prepared to purchase or lease
the property.

Question:
What, if any, is the John Doe family’s liability if a proposed
transaction does not close (a) due to the family’s default or (b) due
to Development Co.’s default.  How might the liability be minimized in
each of the instances referred to in (a) and (b) above?