What is the ruling on performing dry ablution (tayammum) instead of the ritual bath due to severe cold?
Whoever is sick such that he cannot use water, or finds the water cold and heating it is not possible, and the person would be harmed by using cold water, it is permissible for him to perform tayammum. He must make up what he prayed with tayammum, because this is a place where there is water. And Allah the Almighty knows best.
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.
What is the ruling of Islamic Law on speaking with one's fiancée (before the marriage contract) by telephone and WhatsApp?
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah.
Before the marriage contract, the two engaged persons remain non-mahram (strangers) to one another. Reciting al-Fātiḥah, receiving some money on account of the dowry (mahr), or accepting a gift are all merely a promise of marriage and not a valid contract under the Sharīʿah.
It is therefore forbidden for the engaged couple, before the marriage contract is concluded, to be alone together (khalwah) or to shake hands. It is likewise forbidden to speak by telephone or correspond without need. And Allah Almighty knows best.
What is the ruling on offering an Udhiyah on behalf of another with their permission?
Praise be to Allah, and peace and blessings be upon our master, the Messenger of Allah.
It is permissible for a person to offer a sacrifice (Udhiyah) on behalf of someone else with their permission, even if the person performing it has not offered a sacrifice for themselves. It is stated in Sharh Manhaj al-Tullab (Vol.5/P.261) by Zakariya al-Ansari: "No one may offer a sacrifice on behalf of another without their permission... as opposed to when permission has been granted." And Allah the Almighty knows best.