Is it permissible to participate in an Udhiyah?
Praise be to Allah, and peace and blessings be upon our master, the Messenger of Allah.
Regarding the sacrificial offering (Udhiyah), if it is a sheep or a goat, it only avails for one person. However, if it is a cow or a camel, it avails for seven people. It is permissible for the seven participants to have different intentions; for example, some may intend the sacrifice (Udhiyah), some the ’Aqiqah (sacrifice for a newborn), and others may simply intend to obtain meat.
It is stated in Hashiyat Qalyubi ‘ala Sharh al-Mahalli (Vol.4/P.256) and in Bushra al-Karim (p. 706):
"If one slaughters a camel or a cow on behalf of seven... it is permissible. Likewise, it is permissible if some of them intend their seventh for meat, and others intend their seventh for ’Aqiqah." And Allah the Almighty knows best.
What is the correct point at which to raise the hands when standing up for the third rak‘ah (after the middle tashahhud)?
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah ﷺ.
Raising the hands while saying the takbīr [when rising for the third rak‘ah] is a recommended sunnah, and omitting it does not affect the validity of the prayer. The proper time for this is after rising from the middle tashahhud, once one has fully stood up.
It is stated in I‘ānat aṭ-Ṭālibīn (Vol.1/P.158): "His statement, 'and rising from the first tashahhud' — meaning, this manner [of raising the hands] is also a sunnah when he rises from the first tashahhud, that is, when he stands upright from it.
Consider [the question]: when precisely does the raising of the hands begin? Is it at the very start of rising from the first tashahhud, or after he has reached the minimum position of rukū‘ [i.e., once fully upright]? The apparent, [correct] view is the latter — even though the outward wording [of the text] might suggest the former — because at the very start of his rising, he is still relying on both hands [to push himself up, and therefore cannot yet raise them]."
It is stated in ‘Umdat as-Sālik (p. 53): "If his prayer extends beyond two rak‘ahs, he sits after them in the iftirāsh position, recites the tashahhud, and sends blessings upon the Prophet ﷺ alone, without [mentioning] his family [at this point]. He then stands while saying the takbīr, supporting himself with his hands; and once he has stood upright, he raises them level with his shoulders." And Allah, the Exalted, knows best.
Is it obligatory to make up all missed prayers?
All praise is due to Allah, and peace and blessings be upon our master the Messenger of Allah ﷺ.
Making up missed prayers (qaḍāʾ) is a sharʿī obligation, established by the practice of the Prophet ﷺ himself — when the disbelievers preoccupied him on the Day of the Trench and he missed the ʿAṣr prayer, he made it up afterward. This is further affirmed by the ḥadīth: "Fulfil what you owe to Allah, for Allah is most deserving of being fulfilled." (Reported by al-Bukhārī.)
Accordingly, a person who has missed prayers should set aside his voluntary and Sunnah prayers and replace them with make-up prayers in their stead. There is no objection to making up one missed prayer alongside each obligatory prayer that is performed — praying the equivalent missed prayer together with each current obligatory prayer as a practical and manageable way of gradually clearing one's debt of missed prayers. And Allah the Almighty knows best.
Who is the one required to slaughter the 'aqīqah?
All praise is due to Allah, and may peace and blessings be upon our Master, the Messenger of Allah.
It is Sunnah for the 'aqīqah to be slaughtered by the guardian of the newborn — the one upon whom the child's financial maintenance is obligatory — provided he is financially capable of doing so. 'Alī ibn Abī Ṭālib, may Allah be pleased with him, reported: "The Messenger of Allah ﷺ performed the 'aqīqah for al-Ḥasan with one sheep." — Narrated by al-Tirmidhī. And Allah Almighty knows best.