What is the ruling on purchasing Waqf lands located within residential master plans to complete an amputated plot of land, and what is the ruling on purchasing fruitful trees and replacing them with trees from the Waqf to permit their disposal?

The default is for the endowment (waqf) to remain as it is, and for its affairs to be managed according to the conditions set by the waqif (endower), provided they are just and not oppressive. It is not permissible to sell the waqf or dispose of it in a way that removes it from its endowment status, unless the interest (maslaha) of the waqf necessitates it. The trustworthy supervisor (nazir) of the waqf assesses this interest. If the waqf authority deems it appropriate to sell some of the waqf's lands and trees, they are permitted to do so according to the Shariah perspective.