Looking into the history of other historical treasures that DID survive, I have noticed a trend.
Many of these buildings went through a "Decay and Rebirth" stage. Often they were used for low rent apartments, their insides falling apart and decaying.
Then as the Economy in NewYork picked up again in the 80's and 90's they start to be bought out and turned into Luxury Condo's.
In terms of trying to keep it "useful" I agree that tying it together with other near by buildings, mainly the
City Investment Building and of course the
Hudson Terminal.
Considering that these three buildings were cleared to make way for the World Trade centers, The best option I am thinking is buying out All Three Properties and redeveloping them into a massive linked Commercial Complex. That could allow you to have a unified space, and then, as the need for commercial space became truly high in the 70's, Perhaps, you could "Sacrifice" the smaller buildings in between those three for a large WTC office tower.