What is the ruling on taking money from a person who bought an inherited, unregistered plot of land and built a factory on it, then gave some of the original landowners varying monthly salaries, knowing that no one goes to the "ghafrah" (burial plot/grave/tomb) for which these salaries are given?

It is not permissible to issue a fatwa regarding a specific case due to the dispute involved and the lack of knowledge concerning its circumstances. However, generally speaking, if the land is usurped, it is not permissible to work in the factory built upon it, nor to assist the usurper in any way. It is also not permissible for some of the owners of the usurped land to accept a salary from the usurper for working on it, because the land is a right for all its partners. Therefore, it is not permissible for some of them to exclusively take compensation for it without the others. If compensation is received, it must be divided among all those who own the land according to their shares.