Is it permissible for a woman to uncover her face while performing Umrah (minor Hajj)?
The woman while in a state of Ihram (ritual consecration) is obligated to uncover her face and hands, but at the same time permitted to let her head-covering garment drape from her head down over her face when non-Mahram (i.e., marriageable) men pass by her. And Allah Knows Best.
Islamic creed is a comprehensive creed, and if there is any defect, the creed of the individual or group is not correct. Is the creed of the Sufis correct or not?
Sufism is the practice of applying knowledge; this is how Al-Imam Al-Sha'rani defined it. If some among them have deviations in creed, it is not permissible to generalize this to all Sufis, as there are those among them who are acknowledged by all scholars for their knowledge and virtue. And Allah The Almighty Knows Best.
Is it permissible for a Muslim woman to uncover her hair in the presence of a Christian woman?
All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallahu ‘alayhi wa sallam, is His slave and Messenger.
According to the reliable opinion of the Shafie School of Thought, this isn`t permissible. However, some scholars stated that it is permissible for a woman to uncover what she usually uncovers while doing housework, but this differs from one place to another where some women uncover their hair while some don`t. However, this is provided that a woman doesn`t uncover her hair in the presence of non-Mahram men (Men permissible for a woman to marry). And Allah The Almighty Knows Best.
Does Husband fasting while being impure for having sexual intercourse with his wife at night permissible?
Yes it is permissible for you to fast because impurity isn't among valid fasting conditions, but you are obliged to perform ritual impurity in order to catch up Fajr prayer at its due time. And Allah Knows Best.