Who is the "Capable Person" for whom the Udhiyah is recommended?
Praise be to Allah, and peace and blessings be upon our Master, the Messenger of Allah.
The "Capable Person" (Al-Qadir): This refers to anyone who possesses surplus wealth beyond their own essential needs and the financial maintenance of their wife, children, or whoever is under their legal care, during the day of Eid and the three days of Tashreeq (the 11th, 12th, and 13th of Dhul-Hijjah), as this is the designated timeframe for the sacrifice. And Allah Knows Best.
What is the ruling on undoing braids of hair during the ritual bath?
It is not a condition to undo braids if the water reaches all the hair and penetrates to its base. If the water does not reach except by undoing the braids, then it is obligatory to undo them for the water to reach. And Allah the Almighty knows best.
Is it permissible for one who sacrifices on behalf of another, with the latter's permission, to eat from the sacrifice?
It is permissible for someone who sacrificed on behalf of another with their permission to eat from it with their permission, and they stand in their place (act as their representative) in distributing it.
It is stated in Nihayat al-Muhtaj ila Sharh al-Minhaj (Vol.8/P.141): "And he—meaning the one sacrificing on his own behalf, provided he has not apostatized—has the right to eat from a voluntary sacrifice and his sacrificial gift; rather, it is recommended. As for an obligatory sacrifice, it is forbidden for him to eat from it, whether it was designated as such initially or as a liability in his dhimmah. And excluded by what has preceded is if he sacrifices on behalf of another, or if he apostatized, then it is not permissible for him to eat from it, just as it is absolutely impermissible to feed a disbeliever from it."(The text I found indicates the impermissibility of eating) ???
And it is stated in Hashiyat al-Jamal ‘ala Sharh al-Manhaj (Vol.5/P.262): "If a person offers a sacrifice on behalf of a living person with their permission, does he act as their representative in distributing it—on the grounds that permission to sacrifice is permission to distribute it—or does it depend on their explicit permission? This requires consideration, but the first view is not far-fetched." And Allah the Almighty knows best.
What is the ruling of Islamic Law on shaving body hair and clipping the nails for one who is in a state of major ritual impurity (*junub*)?
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah.
It is recommended for one in a state of major ritual impurity (junub) not to remove anything from his body until after the ritual bath (ghusl). It is stated in Bushrā al-Karīm bi-Sharḥ Masāʾil al-Taʿlīm (p. 135): “It is recommended for one in a state of janābah and the like not to remove anything from his body until after ghusl, because the parts of the body return to him in the Hereafter, and he returns in a state of janābah, as a rebuke to him. Then it is removed from him, except for the original parts. It is said that every hair demands its due for its janābah.”
It is stated in Ḥāshiyat al-Shabrāmallisī ʿalā Nihāyat al-Muḥtāj (Vol.2/p.341): “If he wishes to combine shaving and the Friday ghusl, he should delay the shaving until after the ghusl if he is in a state of janābah, so that the ghusl removes its trace from the hair.” And Allah Almighty knows best.