When is it Sunnah 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 on the seventh day from the birth of the newborn. According to the sounder position, the day of birth itself is counted as the first of the seven days. Thus, for example, if the child is born on a Saturday, the 'aqīqah is to be slaughtered on the following Friday. If the child is born at night, the count begins from the day that follows. And Allah Almighty knows best.
Why was the exact date of Laylat al-Qadr concealed?
The wisdom behind this is to encourage Muslims to strive in worship throughout all the nights of Ramadan, or at least in the last ten nights. By doing so, they will earn the reward of observing Laylat al-Qadr as well as the reward of worshiping on other blessed nights.
Is it permissible to offer an Udhiyah on behalf of the deceased?
Praise be to Allah, and peace and blessings be upon our master, the Messenger of Allah.
Offering a sacrifice (Udhiyah) on behalf of the deceased is permissible. This is the position of the Hanbalis [Kashshaf al-Qina’ by al-Bahuti (Vol.6/P.428)], and it was held by al-Abbadi of the Shafi’is [Bidayat al-Muhtaj by Ibn Qadi Shuhbah (Vol.4/P.358)]; it is also narrated from some Maliki and Hanafi scholars.
Abu Dawud included a chapter in his Sunan titled "Chapter: Offering the Sacrifice on Behalf of the Deceased," in which he narrated from Hanash, who said: "I saw Ali (may Allah be pleased with him) sacrificing two rams. I asked him, 'What is this?' He replied, 'The Messenger of Allah (peace be upon him) enjoined me to sacrifice on his behalf, so I am sacrificing on his behalf.'"
Abu Dawud also narrated from Jabir (may Allah be pleased with him) that the Prophet (peace be upon him) said: "O Allah, this is from You and for You, on behalf of Muhammad and his Ummah; in the name of Allah, and Allah is the Greatest," then he slaughtered it. It is well known that among the Ummah of Muhammad (peace be upon him) are those who have passed away, yet he (peace be upon him) dedicated it to his entire Ummah.
Furthermore, multiple Sharia texts have consistently indicated that the rewards of righteous deeds reach the deceased. This includes the permissibility of fasting on behalf of the deceased if they died owing fasts, as well as the permissibility of performing Hajj on their behalf, both of which are established in authentic Hadiths. Since the rewards for fasting—a physical act of worship—and Hajj—a physical and financial act of worship—reach the deceased, then the sacrifice (Udhiyah) is even more likely to reach them.
Moreover, the scholars have reached a consensus (Ijma') that the rewards of charities reach the deceased, and the Udhiyah is a form of charity and falls under its general category. Based on all of this, we hold the view that offering a sacrifice on behalf of the deceased is permissible. And Allah the Almighty knows best.
Is it permissible for a woman to lead other women in prayer?
Yes, it is permissible for a woman to lead other women in prayer. The most knowledgeable among them in the rulings of prayer should act as the imam. She should stand in the middle of the row, slightly ahead of the others.