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.
Is Aqeeqah due on the miscarried embryo?
No Aqeeqah is due on the miscarried embryo.
Is Zakah due on the orphan`s money?
Yes, Zakah is due on the money of the orphan.
What is the ruling on working for orphans' institution?
Praise be to Allah the Lord of the Worlds. May His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
There is no sin in working for orphans` institution. And Allah The Almighty Knows Best.