Is it permissible for one to shake hands with his uncle`s daughter?
No, it isn`t because he is a non-Mahram (Marriageable) to her.
What is the ruling on performing istinja' after passing wind from the anus?
Ablution is invalidated by passing wind from the anus, even without a smell. Only ablution becomes obligatory from it. Istinja' is not obligatory nor recommended. And Allah the Almighty knows best.
How many Rak`ahs (unit of prayer) are offered in Witr prayer?
All perfect praise be to Allah, The Lord of The Worlds Witr (an odd number prayer performed between Isha`a and Fajr) is offered with a minimum of one Rak`ah, and a maximum of eleven, but offering three Rak`ahs is the minimum of its complete form. And Allah Knows Best.
What is the ruling of Islamic Law on Making up Prayers Missed before Reaching Puberty?
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah ﷺ.
Among the conditions for accountability for one's actions in the Hereafter is taklīf (religious legal responsibility) — meaning, possessing sound reason and having reached puberty. The signs of puberty are: nocturnal emission, menstruation, or reaching the age of fifteen [lunar years].
Whoever missed prayers before reaching puberty is not obligated to make them up, since taklīf did not yet apply to him at that time. Our master, the Prophet ﷺ, said: "The pen has been lifted from three: from the child until he reaches puberty, from the sleeping person until he wakes, and from the insane person until he regains sanity." [Related by Abū Dāwūd]
The method for making up missed prayers and fasts has already been explained in Fatwa No.
2705, and Fatwa No.
876. And Allah, the Exalted, knows best.