Is it permissible for a praying person to make supplication in each Sajdah (a prostration) of obligatory prayer?
It is permissible for a praying person, whether praying individually, or in congregation, to make supplication during Sujood (prostration) in obligatory, or voluntary prayers. However, it is disliked for the Imam to do so since he is required to spare the prayer performers any sort of hardship, unless he is leading a certain group who don`t mind him extending the prayer.
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.
Is it permissible for a person, who vowed to offer two Rak`ahs (units of prayer) everyday for Allah`s sake, to do so after the Fajr (dawn) prayer?
In principle, a vow should be fulfilled as it was originally intended, and if its time lapses then, it should be fulfilled at any time because of the vow. Therefore, it is permissible to offer them after the Fajr prayer, and there is no prohibition in doing so. However, it is preferable for him to offer these two Rak`ahs at some other time to avoid the disagreement amongst the scholars in this regard.
What should one who forgot to offer the second Sajda during congregational prayer, and remembered it before the end of the prayer do?
All perfect praise be to Allah, The Lord of The Worlds. Whoever forgets a pillar of prayer while in congregation must follow the lead of the Imam, and after the latter offers Tasleem, he should offer one Rakah, then perform Sujood As-Sahw (prostration of forgetfulness). And Allah Knows Best.