Is it permissible for a sick person to pray while sitting on a chair?
All perfect praise be to Allah, The Lord of the Worlds It is permissible for a sick person, who is unable to stand up, to offer prayer while sitting on a chair. If he/she was unable to prostrate while on the chair, the he/she should pray while sitting on the ground, but if he/she was neither able to bow (Roku),nor to prostrate, then he can do them while sitting on the chair. And Allah Knows Best.
Is it permissible for the guardian to give Sadaqa (voluntary charity) from the money of the orphans?
It is impermissible for the guardian to donate from the money of the orphans because he is entrusted with the safekeeping of that money, and is prohibited from donating it.
What is the ruling on Zakat al-Fitr?
Zakat al-Fitr is obligatory upon every Muslim for themselves and for those they are financially responsible for, provided they possess wealth that is surplus to their and their family's needs on the night and day of Eid.
Ibn Umar reported: "The Messenger of Allah ﷺ made Zakat al-Fitr obligatory—one sa‘ (measure) of dates or one sa‘ of barley—upon every Muslim, whether slave or free, male or female, young or old." [Narrated by Al-Bukhari]
Its estimated amount is approximately 2,500 grams of wheat or rice, and the General Iftaa` Department issues an annual ruling specifying its monetary value.
Is it a condition for the mosque where I‘tikaf is performed to hold Jumu‘ah prayers?
No, it is not a condition for the mosque where I‘tikaf is performed to have Jumu‘ah prayers. However, if a person vows to perform continuous I‘tikaf, and Jumu‘ah occurs within that period, then they must observe I‘tikaf in a mosque where Jumu‘ah is held so that they do not break their continuity by leaving for Friday prayer.