No, you cannot subtract the costs of damages to your property from the amount of money left with you for the previous tenant. Whoever gave you the money is trusting you to give it completely to the previous tenant. This is a trust (amana), and it is prohibited to violate the trust. You can still continue to ask the previous tenant to undertake the repairs or to pay for them.
Just denying the Imamate of Imam Musa al-Kadhim (peace be upon him) does not make the person an enemy of the Imams (a Nasibi). However, if such denial consists of hostility, then based on an obligatory precaution it is not permissible to marry him.
It is reported in the narrations of the Ahlulbait (peace be upon them) that their knowledge is of two kinds: one is the inherited books from Imam Ali (peace be upon him) that he wrote down from the dictations of the Messenger of Allah (peace be upon him). The other kind is the information that they need in their everyday life which they get from Almighty Allah.
