What should a person who doubted having missed a pillar of prayer do?
All praise be to Allah, The Lord of The Worlds. The prayer of one who doubts having missed one of its pillars is valid, and nothing is due on him/her since having a doubt after offering the act of worship doesn`t undermine its validity. And Allah Knows Best.
How many Rak`ahs (unit of prayer) are offered in Witr prayer?
All perfect praise be to Allah, The Lord of The Worlds Witr (an odd number prayer performed between Isha`a and Fajr) is offered with a minimum of one Rak`ah, and a maximum of eleven, but offering three Rak`ahs is the minimum of its complete form. And Allah Knows Best.
What are the Sharia consequences when the sacrificial time for the uḍḥiyyah comes to an end?
All praise is due to Allah, and may peace and blessings be upon our Master, the Messenger of Allah.
If the sun sets at the end of the last of the Days of Tashrīq and the sacrificial animal (uḍḥiyyah) has not yet been slaughtered, then its prescribed time has elapsed. Should one slaughter it thereafter, it will not be considered a valid uḍḥiyyah.
However, if the sacrifice was vowed (mandhūrah), then it remains obligatory to slaughter it — and it shall be carried out as a make-up (qaḍā') of the vow, with its meat distributed in the rightful channels designated for such sacrifices.
It is stated in Bushrā al-Karīm (p. 702): "If one slaughters after the sunset of the last of the Days of Tashrīq... it isn`t considered a valid uḍḥiyyah, unless it was vowed — in which case it is carried out as qaḍā'."
And Allah Almighty knows best.
Is it permissible to offer an absentee funeral prayer?
Yes, it is permissible to offer an absentee funeral prayer.