What is the ruling on congregational prayer performed outside the mosque, and is it a condition that it be performed in a mosque in order to attain the full reward?
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah ﷺ.
It is not a condition for attaining the reward of congregational prayer that it be performed in a mosque; however, a Muslim should still be keen to perform his prayers in the mosque, so as not to miss out on immense reward. This is due to the virtue of the mosque and of spending time there (i‘tikāf), the typically larger number of worshippers present, and the additional reward gained through walking to and from the mosque. On the authority of Abū Hurayrah (raḍiyallāhu ‘anh), the Messenger of Allah ﷺ said: "Whoever purifies himself in his house, then walks to one of the houses of Allah to fulfill one of the obligations Allah has prescribed, one of his steps will erase a sin, and the other will raise him a degree [in status]." (Related by Muslim)
Whoever misses congregational prayer at the mosque should still strive to pray in congregation at his workplace, or together with the members of his household. And Allah, the Exalted, knows best.
Is it permissible to offer an absentee funeral prayer?
Yes, it is permissible to offer an absentee funeral prayer.
What are the valid excuses for abstaining from congregational prayer in the mosque?
Praise be to Allah, and peace and blessings be upon our Master, the Messenger of Allah.
Concessions (Rukhsah) are granted to abstain from congregational prayer in the mosque due to general excuses, such as: rain that causes hardship in going out, strong winds at night, heavy mud that cannot be traversed without the risk of soiling oneself, hot winds, and extreme heat or cold. There are also specific individual excuses, such as: illness that makes walking as difficult as walking in the rain, severe drowsiness, evident hunger or thirst, the suppression of bodily wastes (urine, stool, or gas), and fear for one's life, limb, physical faculty, wealth, or honor, among other valid excuses. And Allah the Exalted knows best.
What is the ruling on the white discharge (*Al-Qassat al-Bayda'*) if it is in a very small amount—is it considered a sign of purity?
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah.
Among the signs of purity (Tahr) for a woman is the white discharge (Al-Qassat al-Bayda'), which is a clear, pure white fluid, regardless of whether it is minimal in quantity, or complete dryness (Jafaf), wherein secretions cease entirely such that if a white cotton cloth is inserted, it comes out completely clean. Once a woman observes either of these two signs, she has attained ritual purity.
Furthermore, another sign of purity is when the duration of the menstrual period exceeds the maximum limit of menstruation, which is fifteen days. If it exceeds this period, it becomes evident that she is experiencing non-menstrual bleeding (Istihadah).