Who should pay the Zakah (obligatory charity) from the orphan`s money?
His/her guardian, and if the latter fails to do so, then the orphan himself/herself is obliged to pay the Zakah once he/she reaches puberty, and is capable of handling his/her own affairs. And Allah Knows Best.
Does sacrificing one sheep avail for the entire household?
Praise be to Allah, and peace and blessings be upon our master, the Messenger of Allah.
In Islamic jurisprudence, the sacrifice (Udhiyah) is considered a Communal Sunnah (Sunnah Kifayah) for the members of a single household who share the same financial support.
If one member of the household performs the sacrifice—even if they are not the primary breadwinner, such as the wife or one of the children—the religious request is fulfilled on behalf of the entire household. This is similar to the Funeral Prayer (Salat al-Janazah), where the obligation is dropped for the community if some perform it.
While the communal request is satisfied by one person's action, the specific spiritual reward (Thawab) for the act of worship belongs only to the person who sacrificed, unless that individual explicitly intends to include the other family members in the reward.
A single sacrifice also avails for a man who is married to more than one wife. And Allah the Almighty knows best.
What are the Sunnahs and etiquettes related to the slaughtering of an animal?
Praise be to Allah, and peace and blessings be upon our master, the Messenger of Allah.
1-The animal should not be terrified or frightened before it is slaughtered.
2-An animal should not be slaughtered in front of other animals.
3-It is recommended to offer water to the animal before it is slaughtered.
4-The knife must be sharpened before the slaughter to ensure that the esophagus, trachea, and jugular veins are severed as quickly and cleanly as possible. This is based on the Prophet’s (peace be upon him) saying: "Verily, Allah has prescribed Ihsan (excellence/proficiency) in all things. So, if you kill, kill well; and if you slaughter, slaughter well. Let each one of you sharpen his blade and let him spare the animal unnecessary suffering." [Narrated by Muslim].
5-One must not begin skinning or butchering the animal until its death has been fully confirmed.
6-Cows and Sheep: It is best to slaughter them while they are lying on their left side, facing the Qiblah. The right hind leg should be left untied so the animal can move it, which helps it remain more comfortable during its final moments. Unlike other livestock, it is preferred to perform Nahr (slaughtering by a swift stab at the base of the neck) while the camel is standing, with its left knee tied. And Allah the Almighty knows best.
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.