Is the `Iddah (waiting period) of the divorced effective from the time the divorce took place, or from the time of registering it at the court?
It is considered effective from the very moment her divorce took place, but not from the time of registering it at the court. And Allah Knows Best.
Is it permissible for a mother to stop her daughter from marrying a respectable, God-fearing young man because he isn't college/university graduate?
It is impermissible to deny a woman her right in getting married except for a lawful reason, and problems can be solved through dialogue. However, she can file a suit in order for the judge to have a say in that regard.
Is it permissible for a Muslim woman to leave her house adorned and without wearing her proper Islamic attire?
A Muslim woman isn't permitted to leave her house adorned and without wearing proper Islamic attire. And Allah Knows Best.
What is the ruling of Sharia on a Muslim woman who committed Zina with a Christian and became pregnant as a result?
All perfect praise be to Allah the Lord of the Worlds. May His peace and blessings be upon Prophet Mohammad and upon all his family and companions.
Abortion is forbidden in Islam as it entails taking the life of a soul unjustly. Rather, it is one of the major sins; however, it is permissible only when there is well-established danger on the mother`s life; in which situation scholars gave priority to her life over that of the foetus, since this is, according to Sharia: "The lesser of two evils". In case a Muslim woman committed Zina (Adultery) with a Christian and got pregnant, if this did happen, then this question should be presented to the Iftaa` Committee with the presence of the questioner herself. She could also ask a reliable scholar face to face or via phone. If she gives birth to the baby, then he/she is a Muslim and takes the name of his mother; not the name of the man who was a reason for its conception. And Allah The Almighty Knows Best.