Intoxicating alcohol is najis and when it touches the body or the clothes, they should be purified before praying or the najis clothing must be removed.
You can change the Marja that you follow based on religious evidence, like for instance when it is proven to you that the new Marja is more knowledgeable than the current one.
It is permissible to give the zakat to the appointed person if he is trustworthy to pass it to whoever deserves it. If one is not sure of his trustworthiness, his payment of Zakat to him is invalid.
