Is the guardianship of a Sufi permissible in a marriage contract if he fulfills the pillars of Islam and believes in Hussein, Sayyida Zaynab, and the occupants of the graves? And if his guardianship is not permissible and the contract has already been concluded, is it necessary to perform a new contract by changing the guardian?

Marriage without a wali (guardian) is invalid. The wali must be a male, of sound mind, an adult, free, and a Muslim. If the wali believes in the righteousness of saints, but does not direct acts of worship to them, then his guardianship is valid. However, if he believes that they can benefit or harm independently of Allah, or if he directs any act of worship to them, then his situation must be examined: if he is ignorant of this, he is excused, and his marriage contract is valid. But if he is aware of the ruling and the proof has been established against him, then he is outside the fold of Islam, and his contract is invalid; it must be renewed with a shar'i (Islamic legal) wali. As for the children, they are legitimate in all circumstances.