Who said it belongs to Gurari, it belongs to the Shul. It is enough that he used it for himself all these years, now they want to sell it? To whom? Is this what the original owners sold it for? So that his kids could make a few dollars. The people who originally owned the buildings were either forced or willingly sold it so that 770 can have more space, not that the buildings should be sold for a profit by PRIVATE individuals.

Rabbi Shaine and the other original owners should take them to a Din Torah

This is one hell of a Chilul Hashem, and I am sure it is against Halacha

But like everything else in Sidom it will probably happen so what is the use fighting.

איפה נטבול בבוקר?

ככה גם כולם יעשו דיאטה חוץ מנקיון