What is the ruling on Jumu‘ah (Friday) prayer for a traveler, and what are the conditions for it to be waived from him?
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah ﷺ.
Jumu‘ah (Friday) prayer is not obligatory upon a traveler, whether on a long or short journey, provided that — according to the Shāfi‘ī school — he departs from his place of residence before the time for Fajr prayer begins, and that he does not intend to stay in the place he travels to for four days or more, excluding the day of arrival and the day of departure. If he intends to stay longer than that, he may not make use of the travel concession simply by arriving in that town. If he begins his journey after the adhān for Fajr has already been called, then Jumu‘ah prayer remains obligatory upon him, whether in his own town or in any town where Jumu‘ah is being held.
It is stated in Bushrā al-Karīm (Vol.1/p.383), from the books of the Shāfi‘ī school: "Jumu‘ah [prayer] is not obligatory upon a traveler on a permissible journey, whether long or short, if he departs from his place of residence before Fajr."
A "short journey" refers to travel covering a distance shorter than that of a long journey — that is, less than (81 km). The traveler begins to be entitled to travel concessions once he passes beyond the built-up limits of his town. And Allah, the Exalted, knows best.
Should missed Sunnah prayer be made up?
Making up missed voluntary acts of worship is from Sunnah.
Is the niṣāb calculated based on the price of 21-karat gold, or 24-karat gold?
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah ﷺ.
Zakāh is obligatory on cash and on gold designated for saving or for trade, provided the total reaches the niṣāb (minimum threshold liable for zakah), and a full ḥawl (lunar year) has elapsed over it. The niṣāb is (85) grams of 24-karat gold; for 21-karat gold, the niṣāb equals (97) grams; and for 18-karat gold, it equals (113) grams.
The relied-upon position is to calculate the zakāh based on the buying price [i.e., the price the gold merchant would pay the owner to purchase the gold from him] on the day the zakāh obligation is due.
The one paying zakāh may assess/calculate the niṣāb using any of the aforementioned gold karats [i.e., he may choose whichever karat standard he wishes for the purpose of the calculation]. And Allah, the Exalted, 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.