Does buying meat equivalent to the weight of a slaughtered animal and distributing it avail for an udhiyah?
Praise be to Allah, and prayers and peace be upon our Master the Messenger of Allah.
That does not avail for the sacrifice (uḍḥiyyah), because the sacrifice necessarily requires slaughtering an animal from the category of anʿām (camels, cattle, and sheep/goats) within a specified time.
Rather, that is considered a form of charity (ṣadaqah) for which one is rewarded, but not an udhiyah. And Allah Almighty knows best.
What is the ruling on ablution without istinja' after sleep?
The sleep of one whose buttocks are not firmly seated on the ground invalidates ablution. Whoever wakes up and wants to pray must perform ablution only. Istinja' is not a condition for the validity of ablution, because it is for removing impurity from the private part. If there is no impurity on the private part, then istinja' is neither obligatory nor recommended. And Allah the Almighty knows best.
Is the one offering the sacrifice liable if its meat spoils?
Praise be to Allah, and prayers and peace be upon our Master the Messenger of Allah.
If the meat (of the sacrifice) spoils due to the negligence of the one offering the sacrifice in preserving it, or due to improper storage, then he is liable to compensate for the portion due to the poor (which is estimated as half a kilogram of meat). If the sacrifice was a vowed (mandatory) one, then he is liable for all of it.
However, if he was not negligent, then there is no liability upon him, because its ruling is the ruling of a trust (like an item left in someone's care). And Allah Almighty knows best.
What are the Sunnahs and etiquettes related to the slaughtering of an animal?
In the Name of Allah, and may peace and blessings be upon our Master, the Messenger of Allah.
1-Avoid terrifying the animal before it is slaughtered.
2-Do not slaughter the animal in front of others of its kind.
3-Offer water to the animal before the sacrifice.
4-Sharpen the knife thoroughly prior to slaughtering to ensure the cut is made as quickly and cleanly as possible. This is in accordance with the statement of our Master, the Prophet (peace and blessings be upon him): "Indeed, Allah, the Almighty and Majestic, has prescribed excellence (Ihsan) in all things. So when you kill, kill well; and when you slaughter, slaughter well. Let each of you sharpen his blade, and let him put his sacrificial animal at ease." (Narrated by Muslim)
Do not begin skinning the carcass until you are absolutely certain that the animal has completely passed away.
Slaughter cattle, sheep, and goats while they are lying down on their left side, facing the Qiblah (direction of prayer). Leave the right leg untied so the animal can move it, helping it rest more easily during its final moments. For camels, however, the preferred method (Nahr) is to slaughter them while they are standing up, with their left knee tied. And Allah the Almighty Knows Best.