What should a person who doubted having missed a pillar of prayer do?
All praise be to Allah, The Lord of The Worlds. The prayer of one who doubts having missed one of its pillars is valid, and nothing is due on him/her since having a doubt after offering the act of worship doesn`t undermine its validity. And Allah Knows Best.
What is the ruling of Islamic Law on performing the Witr prayer after the Adhan for Fajr prayer?
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah ﷺ.
The time for Witr prayer begins after the ‘Ishā' prayer and ends with the rising of true dawn (al-fajr aṣ-ṣādiq). If a Muslim performs it at any point within this window, it counts as performed on time.
It is also recommended to make up a missed Witr prayer at any time — whether before or after performing the Fajr prayer, or at any other time of day. On the authority of Abū Sa‘īd al-Khudrī (raḍiyallāhu ‘anh), the Messenger of Allah ﷺ said: "Whoever falls asleep and misses the Witr prayer, or forgets it, let him pray it when he remembers, or when he wakes up." (Related by at-Tirmidhī)
Shaykh al-Islām, Imam Ibn Ḥajar al-Haytamī (raḥimahullāh), says: "The time for Witr prayer is between the ‘Ishā' prayer and the rising of dawn, based on the authentic ḥadīth to this effect. If this time has passed, it is permissible for him to make it up (qaḍā') afterward." [Tuḥfat al-Muḥtāj]. And Allah, the Exalted, knows best.
Is it valid to have Suhoor before sleeping, even if it is before midnight?
Suhoor refers to the pre-dawn meal eaten after midnight to help a Muslim endure fasting. The closer it is to Fajr, the better.
The Prophet ﷺ said: "My Ummah will remain upon goodness as long as they hasten to break the fast and delay Suhoor." [Narrated by Ahmad]
This is because delaying Suhoor makes it more effective in providing strength for worship. However, if there is a risk of Fajr entering while eating, one should refrain from Suhoor out of caution.
The Prophet ﷺ said: "Leave what makes you doubt for what does not make you doubt." [Narrated by Al-Tirmidhi]
Is bleeding that lasts for nine or ten days considered menstruation (Hayd)?
Praise be to Allah, and peace and blessings be upon our Master, the Messenger of Allah.
If the duration of the bleeding does not exceed fifteen days, then all of it is considered menstruation (Hayd), even if the regular cycle ('Adah) has changed. And Allah the Exalted knows best.