Should a person feel pleased, or have a virtuous vision after offering Istikhara (guidance prayer) in order to do what he/she had offered it for?
The result of the Istikhaarah is not necessarily that a person sees something (in his dream), or feels pleased, but the most important result of the Istikhaarah is whether a person is enabled to do a given matter or not.
What is the ruling on someone who vowed to fast for two consecutive months, but failed to do so?
He is obliged to fulfill his vow by fasting for two consecutive months, but if he fails to do so then, it remains a debt on him until he either fulfills his vow, or dies. In case of his death, his guardian is supposed to fast on his behalf, or donate food from his estate in return for fasting, but if the guardian fails to do so then, it is all in the Hands of Allah.
I used artificial nails on my wedding night, but I was surprised to find out that they require at least a week to remove. However, I performed all my prayers during that period. What is the ruling on those prayers?
If these nails prevent water from reaching one's skin then your prayer are invalid and obliged to redo all of them. And Allah Knows Best.
What is the stance of Ahlus-Sunnah wal-Jama'ah regarding the historical figure known as 'the Sufyani,' who some say will appear at the end of times? And what is the stance of Ahlus-Sunnah wal-Jama'ah regarding the group that killed Al-Husayn ibn Ali (may Allah be pleased with them), particularly those who directly committed the killing, severed his head, and killed members of his family?
Most of the narrations about the signs of the Hour concerning the Sufyani, who is said to appear before the Mahdi, indicate that he is the leader of the army that will invade the Kaaba, and Allah will cause the earth to swallow them. We disassociate ourselves before Allah from those who killed Al-Husayn Ibn Ali (may Allah be pleased with them), supported his killing, or encouraged it, whether openly or secretly. The inner matters are left to Allah alone. And Allah The Almighty Knows Best.