Is it permissible to openly announce the engagement of a woman who is in her waiting period (iddah)?
It is not permissible to openly announce the engagement of a woman in her waiting period (Iddah), but it is permissible to hint (imply) at it if she is in her waiting period after the death of her husband. And Allah Knows Best.
Is permissible to buy/sell with non-Muslim?
Yes buying/selling for a Muslim with non-Muslim is permissible as regards what is lawful.
What is the Islamic ruling regarding a person finding buried treasure, whether gold or artifacts, and what is their share of it?
If the buried treasure is Islamic, it is considered Luqta (lost property), and the finder must announce it to locate its owner. If all efforts to find the owner fail, the finder may take ownership of it. If the treasure is non-Islamic and consists of gold or silver, zakat must be paid on it, which is one-fifth of its value. And Allah Knows Best.
It was found out that a man divorced his wife for the third time in 2005, but they continued cohabiting as man and wife. However, when they realized that what they were doing was unlawful, they came the Iftaa` Department in 2009 and were told that they can`t be together. What is the position of Sharia on this couple?
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.
Her Iddah* period starts after the third divorce. As for the continued cohabitation, it is unlawful because being ignorant about the rulings of Sharia while in Dar Al-Islam* is no valid excuse. If a baby came as the fruit of this unlawful consummation of marriage, then a judge of Sharia has the final say in this regard because lineage is a serious matter. And Allah The Almighty Knows Best.
* ʿIddah: a specified period of time that must elapse before a Muslim widow or divorcee may legitimately remarry. The Qurʾān (Sura,2/verse,228) prescribes that a menstruating woman have three monthly periods before contracting a new marriage; the required delay for a nonmenstruating woman is three lunar months.
* Dar Al-Islam: designates a territory where Muslims are free to practice their religion, though this often implies the implementation of Islamic law, whereas Dar al-Harb represents those lands ruled by non-believers
