If a woman makes a vow to slaughter a sheep, and her husband is the one who buys it for her from his own money, and he says: "It is for you until you fulfill your vow with it," Is this permissible, or must she buy it herself from her own money?
If her husband gave her the sheep as a donation for the puprose of fulfilling the oath she made and was slaughtered by the wife or the husband on her behalf then the vow she made is fulfilled. And Allah Knows Best.
We collect funds from mosques and other sources, saying: "For the poor, the needy, widows, orphans, and those who do not beg insistently." After paying the stipends of the families registered with the Zakat Committee, an amount exceeding 6,000 dinars remained. Is it permissible for me to save it for upcoming months when I may not be able to collect the stipends?
These funds are received by the committee as representatives of the zakat payers to deliver zakat to those entitled to it. It is well-known that delaying zakat while being able to pay it is not permissible. Imam Al-Nawawi (may Allah have mercy on him) said: "Zakat must be paid immediately if one is able to do so, by the presence of wealth and the eligible categories." [Al-Minhaj] Therefore, the committee must distribute the zakat to the eligible recipients without installment payments or using it to purchase material goods for them, as the committee does not have authority over the poor to allocate it in this way. And Allah Knows Best.
Is it permissible for a woman in her waiting period (Iddah) after her husband's death to leave her house and mix with non-Mahrams?
It is not permissible for a woman in her waiting period (Iddah) after the death of her husband to leave her house except for a necessity, such as for medical treatment, nor is she allowed to mix with non-Mahrams. A woman is not permitted to mix with anyone other than her husband or Mahrams, whether she is in her waiting period or not. However, there is no harm in accepting condolences from those who visit and responding to their inquiries about her well-being. And Allah Knows Best.
Is it permissible to repeat the Istikhara (seeking guidance) prayer, and is it a condition that one should sleep after offering it?
All perfect praise be to Allah,The Lord of The Worlds Istikhara is offered once, but it is permissible to repeat it, and sleeping after offering it is not a condition for its validity. And Allah Knows Best.