If the menses lasted for over than 9 to 10 days, considered menstruation?
If the duration of the bleeding does not exceed fifteen days, it is all considered menstruation, even if the usual pattern changes.
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.
Is the multiplication of reward for prayer in the sanctuaries of Makkah and Madīnah limited to the obligatory prayer, or does it include the voluntary prayer as well?
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah.
There is no difference between the obligatory (farḍ) and the voluntary (nafl) prayer in the ḥadīth on the multiplication of reward in the two Sanctuaries (al-Ḥaramayn), because the authentic ḥadīths are unrestricted and general in wording. It is therefore not permissible to restrict or specify them without evidence. Shaykh al-Islām Imam al-Nawawī (may Allah have mercy on him) said: “Our school holds that the superiority of prayer in the two mosques of Makkah and Madīnah is not limited to the obligatory prayer, but includes both the obligatory and the voluntary.” [al-Majmūʿ Sharḥ al-Muhadhdhab, Vol.8/p.476]
The multiplication of reward applies to whoever prays in al-Masjid al-Ḥarām or anywhere within the sanctuary (ḥaram). Al-Shirwānī (may Allah have mercy on him) said: “The more correct view according to al-Nawawī is that the multiplication of the prayer’s reward covers the whole sanctuary, and is not limited to the mosque, nor to Makkah itself.” [Tuḥfat al-Muḥtāj with the glosses of al-Shirwānī and al-ʿAbbādī, Vol.10/p.95]. And Allah Almighty knows best.
Is the son of the sister by breastfeeding considered a mahram in Islam, and is it permissible for a woman to go for Hajj with him?
Everything that is prohibited by lineage is also prohibited by breastfeeding. The son of the sister by breastfeeding is considered a mahram, just like the son of the sister by blood, and it is permissible for him to be her mahram for Hajj and Umrah. And Allah Knows Best.