Is it permissible for a wife to refuse to go to bed with her husband (for sexual intercourse)?

It isn`t permissible for her to do so unless for a sound reason.

What is the ruling on performing voluntary prayers during official working hours?

All perfect praise be to Allah, The Lord of The Worlds, and may His Peace and Blessings be upon our Prophet Muhammad and upon all of his family and companions

There is no harm if  there was break time during official working hours, but if not then it is impermissible. And Allah Knows Best.

What is the ruling o associations (Whereas a person who have money buys a commodity for a person and  and gets a profit on it)?

It is permissible for a person to buy a commodity for someone's else and have a profit/loss on it

Is the Aqeeqa due on the newborn in case of dying almost a month after the delivery?