What is the ruling on undoing braids of hair during the ritual bath?
It is not a condition to undo braids if the water reaches all the hair and penetrates to its base. If the water does not reach except by undoing the braids, then it is obligatory to undo them for the water to reach. And Allah the Almighty knows best.
What is the ruling on performing the Duha (forenoon) prayer before its time has begun, because I go to school early in the morning?
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah.
The Duha (forenoon) prayer is not valid if performed before its time has begun. Its time starts when the sun has risen to a noticeable height, that is, approximately fifteen minutes after sunrise, and it ends when the sun reaches its zenith (zawāl), shortly before the Dhuhr (noon) prayer. It is stated in Mughni al-Muhtaj (Vol.1/p.455): “Its time is from the rising of the sun [to a spear’s height] until the zenith.”
Accordingly, the Duha prayer is not valid if offered before the sun has risen, and its time remains open until just before Dhuhr. It may be performed at any time at school, during the break between classes or during recess. And Allah Almighty knows best.
What is the ruling on a vowed animal sacrifice?
A vowed animal sacrifice is to be distributed amongst the poor and needy, and neither the vow-maker, nor those supported by him are to eat from it.
What is the ruling on performing istinja' before every ablution?
Istinja' is not from the conditions for the validity of ablution. It is only obligatory for prayer when there is impurity from urine or stool on the private part, or if there is fear of the impurity spreading to the body or clothing. And Allah the Almighty knows best.