Is it permissible to give multiple mudds (portions) of fidyah to a single person?
Yes, it is permissible to give multiple mudd of fidyah to a single person, because each day of fasting is considered an independent act of worship.
What is the ruling on selling sacrificial animals (udhiyah) described with specific attributes and authorizing an agent to slaughter them?
Praise be to Allah, and peace and blessings be upon our Master, the Messenger of Allah.
Selling sacrificial animals (udhiyah) that are described with specific attributes is permissible. This falls under the category of a salam sale (forward sale) if conducted using the terminology of salam, and under the category of a regular sale if not using the terminology of salam.
As for authorizing the seller to slaughter the sacrificial animal, the basic principle is that it is permissible, because the agent (wakil) stands in the place of the principal (muwakkil) in achieving his objective. This is a contract that the principal (the buyer) is entitled to perform himself, so authorizing another (the seller) to do so on his behalf is valid.
However, it is a condition for authorization to slaughter that the intention (niyyah) is present either at the time of slaughter or at the time of handing over the sacrificial animal to the agent. The basic principle is that the sacrificial animal must be specifically designated, as it is an act of worship. It is not required to designate it at the time of slaughter; rather, it is valid to do so before that.
It is permissible for the principal either to delegate the intention to the agent or to formulate it himself when authorizing the agent to slaughter. However, the sacrificial animal must be designated, even if at the time of slaughter, by the agent.
It is obligatory to designate the sacrificial animals so that each person offering a sacrifice receives his own specific animal. Therefore, charitable organizations and companies must take this into consideration and establish a specific mechanism that ensures no mixing of sacrificial animals occurs, so that each person offering a sacrifice receives his own designated animal. And Allah Almighty knows best.
What is the ruling on performing Tahajjud after the Witr?
Praise be to Allah, and peace and blessings be upon our Master, the Messenger of Allah.
It is permissible for one who has prayed the Witr to perform voluntary (Nafl) prayers after it. However, it is preferable for the Witr to be the final prayer of the night. Therefore, if a person is confident that they will wake up during the night for Tahajjud, it is recommended for them to delay the Witr until after the Tahajjud. Conversely, if one fears they may not wake up, they should perform the Witr before sleeping.
Al-Khatib al-Shirbini (may Allah have mercy on him) stated: 'It is not disliked (Makruh) to perform Tahajjud after the Witr, but it is not recommended to do so intentionally.' [Mughni al-Muhtaj, Vol. 1/P.454]. And Allah the Exalted knows best."
Are school exams a valid excuse for breaking the fast in Ramadan?
School and university exams are not considered a valid excuse for breaking the fast, as most students take their exams while fasting without experiencing extreme hardship. Fasting does not conflict with exam preparation, and a Muslim seeks strength in obedience to Allah for both worldly and spiritual matters.