Is the marriage contract considered valid if concluded at home by the marriage official (Ma`zon)?
Yes, it is valid as long as it is registered at the court.
What is the ruling on one who slept while firmly seated on the ground, regarding nullification of ablution?
The default ruling regarding sleep is that it nullifies ablution. An exception to this is one who slept while firmly seated on the ground; his ablution is not nullified by sleep if he wakes up while still firmly seated on the ground. And Allah the Almighty knows best.
When is Istikharah (guidance prayer) Du`a offered, before Tasleem (saying asalamu alikum warahmatu allah wa barakatuh to end the prayer), or after it?
It is offered after Tasleem.
In the Sharia-compliant viewing at a prospective bride (*al-naẓrah al-sharʿiyyah*), is it permissible for the man to see the woman without a veil (*ḥijāb*)?
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah.
It is sunnah for the suitor to see the woman he is seeking to marry within the limits the Sharīʿah permits, namely looking at the face and the hands (palms and backs), based on the saying of the Prophet (peace and blessings be upon him): “Look at her, for it is more likely to bring about harmony between you.” Narrated by al-Tirmidhī.
The suitor may also ask one of the women to look at the woman he is seeking to marry. In that case, she is permitted to see of her what she is normally permitted to see, which is not limited to the face and hands, and she then describes these matters to the suitor. It is narrated on the authority of Anas (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) sent Umm Sulaym to look at a girl, and said: “Smell her breath, and look at her heels.” Narrated by Aḥmad in his Musnad.
It is stated in Tuḥfat al-Muḥtāj (Vol.7/p.192): “For one who cannot easily look, or does not wish to look himself, it is sunnah to send someone who is permitted to look at her, to observe her and describe her to him, even regarding what he himself is not permitted to look at. He thereby gains through the sending what he would not gain through looking. Because of the added need for this, it is excepted from the prohibition of a woman describing another woman to a man.”
The permissibility of looking is conditional upon his resolve to marry her once he is able to, his predominant assumption that his proposal will be accepted, and his assumption that the woman is free of marriage and of a waiting period (ʿiddah). Otherwise, looking is forbidden.
Accordingly, it is not permissible for the suitor to look at anything other than the face and hands. He may ask one of his maḥram women, such as his mother or sister, to see the woman unveiled, and the Sharia-compliant viewing (of a prospective bride) must take place in the presence of one of the woman’s maḥrams. And Allah Almighty knows best.