Is washing the private part after urinating (Istinjaa`) a condition, and is it done with water and soap, or with water only?
Istinjaa` is obligatory for removing impurity, and it can be done with toilet paper, or a stone, or water. It is preferable to do Istinjaa` first with paper, or stone, or the like, then to wash the private part with water until making sure that the impurity has been removed. Using soap is not a condition, but there is no harm in doing so provided that it is washed off with water. It is also permissible to use either water, or paper if impurity is removed by any.
What is the ruling of Islamic Law on performing ṭawāf on the upper floors of al-Masjid al-Ḥarām, given that these floors are situated above the level of the Ka‘bah, and that the one performing ṭawāf passes by certain barriers, such as pillars and walls, during the ṭawāf?
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah ﷺ.
There are numerous conditions for the validity of ṭawāf (circumambulation around the Ka‘bah), among them: that the one performing ṭawāf be inside the Masjid (al-Masjid al-Ḥarām) — even if the Masjid has been expanded, so long as the expansion does not extend out into al-ḥill (land outside the sanctuary boundaries). It suffices for the ṭawāf to be performed in the airspace of the Masjid or upon its roof, even if that roof is higher than the Ka‘bah (the House) itself.
Al-Khaṭīb ash-Shirbīnī (raḥimahullāh) said: "It [ṭawāf] is valid upon the roof of the Masjid, even if the roof of the Masjid is higher than the House — just as prayer [is valid] upon Mount Abū Qubays despite its elevation above the House. This is the relied-upon (mu‘tamad) position." [Mughnī al-Muḥtāj, Vol.2/P.246]
The validity of the tawaf isn`t affected by the pillars and walls standing between the one performing ṭawāf and the House, since the condition is only that the person performing ṭawāf be within the boundaries of the Masjid and outside the boundaries of the Ka‘bah itself.
Ash-Shirbīnī said: "It [ṭawāf] is valid inside the Masjid, even if it is expanded, and even if a barrier stands between the one circumambulating and the House — such as a water-supply structure (saqāyah) or pillars (sawārī)." [Mughnī al-Muḥtāj, Vol. 2/P.246]
Accordingly, ṭawāf performed on the upper floors is valid, and the presence of barriers such as pillars and walls during the ṭawāf does not affect its validity. And Allah, the Exalted, knows best.
What is the ruling on eating or drinking during the second Adhan?
It is not permissible to eat or drink during the second Adhan because it announces the break of dawn and the obligation to start fasting. Allah Almighty says {what means}:"and eat and drink until you can discern the white streak of dawn against the blackness of night." [Al-Baqarah/187].
Whoever eats or drinks during this time invalidates their fast, and they must refrain from eating for the rest of the day and make up for the missed fast later.
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.