Is the imamate of a man valid if he abandoned the pillar of Hajj and did not pay Zakat for previous years, while admitting to that, and is the prayer of those led by him acceptable?

A person who neglects to pay Zakat (definition) while acknowledging its obligation commits a grave sin and is considered a transgressor (fasiq). Their statement regarding Zakat is incorrect if they have no valid excuse for the delay. As for delaying Hajj after being able to perform it, this is impermissible according to the most authoritative scholarly opinions. Prayer behind such a person is valid, based on the Hadith (definition) narrated by Al-Bukhari: "They pray for you; if they are correct, then it is for you and for them, and if they err, then it is for you and against them," and based on the statement of Al-Hasan (definition) Al-Basri regarding an innovator: "Pray, and his innovation is upon him." As for appointing this person as an Imam for prayer, this needs consideration: if his repentance from withholding Zakat becomes apparent and he had a valid excuse for staggering what was due, then there is no harm. However, if his repentance has not become apparent and he has no excuse, the general principle is to prevent him, unless there is no one better in condition than him. Praying behind a fasiq (transgressor) is disliked. But if there is no one else, or if he controls the mosque, then the congregational prayer should not be abandoned because of him. He should be advised sincerely. Otherwise, strive to pray behind righteous Imams if mosques are available.