Does Laylat al-Qadr move between the nights of Ramadan?
Laylat al-Qadr is definitely in Ramadan, and it is most likely in the last ten nights, especially on the odd-numbered nights.
For this reason, the Prophet ﷺ commanded observing worship in the last ten nights, and he himself used to dedicate those nights to worship. Many people put special effort into the 27th night of Ramadan, and they are rewarded in any case, whether they actually coincide with Laylat al-Qadr or not, because worshiping on any night of Ramadan carries great rewards.
What is the ruling on discharging one's zakāh obligation through the provision of a specific benefit (manfa‘ah) — such as performing a surgical operation for a patient, or providing housing to a tenant, and counting the value of this service as zakāh?
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah ﷺ.
It is obligatory to pay zakāh from the actual asset (‘ayn al-māl) upon which zakāh is due, except in the case of zakāh on trade goods ('urūḍ at-tijārah), which is paid based on their monetary value. In all cases, zakāh must be given in the form of tamlīk (a full transfer of ownership), based on the words of Allah, the Mighty and Majestic (which mean): "Zakāh expenditures are only for the poor and for the needy, and for those employed to collect [zakāh], and for bringing hearts together [for Islam], and for freeing captives [or slaves], and for those in debt, and for the cause of Allah, and for the [stranded] traveler — an obligation [imposed] by Allah. And Allah is Knowing and Wise" [at-Tawbah/60]. The letter "lām" (لِ) in this verse — as in "lil-fuqarā'" ("for the poor") — indicates possession/ownership (lām al-milk).
It is not permissible to fulfill one's zakāh obligation by providing a benefit or service (manfa‘ah) — such as housing, education, or medical treatment — in place of the zakāh itself. This is because zakāh must be paid as wealth (māl) that is transferred into the ownership of the poor recipient, whereas such services are intangible benefits that are not, in themselves, capable of being formally transferred in ownership (ghayr qābilah lit-tamlīk). And Allah, the Exalted, knows best.
What is the ruling on performing Tarawih in sets of four rak‘ahs with only one Tasleem?
It is not permissible to combine more than two rak‘ahs with a single Tasleem in Tarawih prayer. Whoever does so, their prayer is invalid. Shaykh al-Islam Imam Muhammad al-Ramli (may Allah have mercy on him) stated: "If a person prays four rak‘ahs of the Tarawih prayer with a single Tasleem, it is not valid if they did so intentionally and with knowledge [of the prohibition]. Otherwise, it becomes an 'absolute voluntary prayer' (nafl mutlaq); because it is contrary to what has been prescribed." [Nihayat al-Muhtaj, Vol.2/P.127].
What is the ruling on someone who is uncertain whether he omitted one of the ab‘āḍ of the prayer, such as being uncertain whether he omitted the first tashahhud?
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah ﷺ.
The ab‘āḍ include the middle tashahhud and the qunūt in Fajr prayer — for which sujūd as-sahw (the prostration of forgetfulness) is prescribed if left out. Whoever is uncertain, during the prayer, whether he omitted one of these elements, should proceed on the assumption that he did not perform it, and should perform sujūd as-sahw accordingly.
It is stated in ‘Umdat as-Sālik (p. 63): "If he is uncertain... whether he omitted a specific ab‘āḍ element, or whether he performed sujūd as-sahw, or whether he prayed three or four rak‘ahs — he proceeds on the assumption that he did not do it, and performs sujūd as-sahw."
The original principle (al-aṣl) for someone uncertain about [having performed] the first tashahhud is that he assumes he did not perform it. And Allah, the Exalted, knows best.