Is it permissible for a person who has to make up for missed fasts to fast six days of Shawwal (the month directly after Ramadan) before making up for the missed fasts?
Yes, it is permissible for him/her to do so, but it is better that they make up for missed fasts first. And Allah Knows Best.
Is a wife considered divorced if her husband refused to go to bed with her (for sexual intercourse) for two months?
A wife doesn`t get divorced no matter for how long her husband refuses to have sex with her, and she had better go to court.
Is it permissible to perform Tayammum for a month due to a medical condition that requires avoiding water?
Tayammum is permissible so long as the above excuse lasts. And Allah Knows Best.
A man married a woman at the Islamic Centre in Brussels through a regular marriage contract. However, the husband left her for two years now and never provided her with financial support. Currently, she is staying in Amman, Jordan, and wants to remarry. Is her first marriage considered void and what should she do to remarry lawfully?
All perfect praise be to Allah, the Lord of the Worlds; may His blessings and peace be upon our Prophet Mohammad and upon all his family and companions.
This issue is within the jurisdiction of the Islamic courts and they have the final say regarding the dissolution of the first marriage contract if there is valid ground for that. Therefore, her first marriage remains valid unless a court decision says otherwise. And Allah The Almighty Knows Best.