Is Zakah due on the orphan`s money?
Yes, Zakah is due on the money of the orphan.
Is it permissible for the children of a deceased father to settle his debt from the Zakah(obligatory charity) money due on them?
It is impermissible to use the Zakah of one`s money for settling the debts of the deceased. However, children should settle the debts of their deceased parents out of filial piety.
Is it permissible for a Muslim woman to go out wearing adornment and not putting on her Hijjab (Islamic wear)?
It is impermissible for a Muslim woman to go out wearing adornment, and not having her Hijjab on.
Is it permissible to pay the expiation of an oath to a charitable party as it feeds the poor and needy such as Tkiyet Um Ali?
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 on authorizing someone to handle the expiation of another to the poor and needy, since Shafiee's jurists stated that authorizing someone for the purpose of distributing Zakah, expiation and vow is permissible as stated in [Mughni Al-Muhtajj, vol.3 pp.237]. At last, the intention of the person who intends to authorize someone else suffices in this regard. And Allah Knows Best.