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.
Is it valid to have Suhoor before sleeping, even if it is before midnight?
Suhoor refers to the pre-dawn meal eaten after midnight to help a Muslim endure fasting. The closer it is to Fajr, the better.
The Prophet ﷺ said: "My Ummah will remain upon goodness as long as they hasten to break the fast and delay Suhoor." [Narrated by Ahmad]
This is because delaying Suhoor makes it more effective in providing strength for worship. However, if there is a risk of Fajr entering while eating, one should refrain from Suhoor out of caution.
The Prophet ﷺ said: "Leave what makes you doubt for what does not make you doubt." [Narrated by Al-Tirmidhi]
Which is superior: The Udhiyah (Sacrificial Offering) or giving its value in Charity (Sadaqah)?
Praise be to Allah, and peace and blessings be upon our Master, the Messenger of Allah.
Performing the Udhiyah (sacrificial offering) is superior to giving its monetary value as charity (Sadaqah) to the poor and needy. This is because the Udhiyah is one of the manifest symbols of the religion. Allah the Almighty says {what means}: "That [is so]. And whoever honors the symbols of Allah - indeed, it is from the piety of hearts." [Al-Hajj/32]. This is further supported by the explicit and authentic Hadiths regarding its virtue, and the fact that the Prophet ﷺ and the Rightly Guided Caliphs after him consistently performed the sacrifice. And Allah the Exalted knows best.
What is the ruling on wiping the head during ablution from behind a barrier like a headscarf (hijab)?
The obligation in ablution is to wipe some of the head; it is not a condition to wipe all of it. As for one who has a turban or headscarf on their head, it is permissible for them to wipe over it after wiping a part of their head in any place. This is easily done at the front of the head. This means the woman begins by wiping the front of her head from under the headscarf, then completes the wiping to the back of the head from over the headscarf. If the woman wipes over the headscarf on her head and the moisture reaches the scalp or some hair within the boundaries of the head, it suffices for wiping the head. And Allah the Almighty knows best.