Answer
(Fatwa: 1174/1174=M/1430)
(1) Performing tarawih 20 rak?ah is sunnah, it is agreed upon by the Sahabah. The Four Imams are also unanimous on this issue and it is reported by the early ulama with abundant chains. 20 rak?ah tarawih is performed in Haramain Sharifain. Therefore, you should perform 20 rak?ah tarawih and should not perform behind an imam who recites looking in the Quran.
(2) You can give Zakah to your brother and sister if they are poor and deserve Zakah.
(3) You can pay Zakah bit by bit, but it is better to pay it off as early as possible, it is not proper to delay it.
Allah (Subhana Wa Ta’ala) knows Best
Darul Ifta,
Darul Uloom Deoband