What is the ruling on working for a company that manufactures cigarettes?
Working for a company that manufactures cigarettes is forbidden because smoking itself is forbidden, so its production, selling and circulation are forbidden as a result since they aid in committing sin, and whoever aids in that is like the sinner himself.
What is the ruling on performing voluntary prayers during official working hours?
There is no harm if there was break time during official working hours, but if not then it is impermissible. And Allah Knows Best.
Is it permissible for a woman to uncover her face while performing Umrah(minor Hajj)?
The woman who is in a state of Ihram(ritual consecration) should uncover her face and hands, but it is permissible for her to let her head-covering garment drape from her head down over her face when non-Mahram (i.e., marriageable) men pass by her.
What is the ruling on singing and listening to it while accompanied and unaccompanied by musical instruments?
Singing and listening to it unaccompanied by musical instruments is permissible as long as it isn`t practiced as a profession and is done by a man to other men, or a woman to other women with maintaining that no temptations are involved. The words of the song should be Islamic, and if temptation was likely to happen, then the singing becomes definitely forbidden. Temptation here means: whatever leads to committing a sin. In Islamic Sharia, singing accompanied by musical instruments such as the lute and the like is forbidden, and listening to it as well. The reason behind that is the fact that the musical instrument itself is forbidden. However, striking the tambourine and singing Islamic songs are permissible in weddings, circumcisions and the like.