Is the Woman wearing an Islamic veil permitted to uncover the veil in front of her brother in law, husband of paternal uncle`s daughter and husband of sister in law?  

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 a woman`s face an Awrah (a private part) that should be covered?

During prayer, a woman`s whole body is a private part except the hands and the face. Outside the time of prayer, scholars agree that a woman should put on her Islamic wear to avoid temptation.