Is it permissible to combine and shorten prayers at home before traveling?
It is impermissible to combine and shorten prayers at home before traveling because a person is called a traveler once he/she departs the borders of his/her country, and offering prayer that way was originally intended to exempt a traveler. And Allah Knows Best.
If someone starts the day sick or traveling while fasting, is it permissible for them to break their fast?
● A sick person who finds fasting difficult is allowed to break their fast, whether they began the day fasting or not.
● As for a traveler:
○ If they were still at home at dawn and then traveled after Fajr (dawn), they must continue fasting unless they experience extreme hardship, in which case they may break their fast.
○ However, if they were already traveling when dawn broke—meaning they had left their town before Fajr—then they are permitted to break their fast. This is what the Prophetﷺ did during the year of the conquest (of Makkah).
What is the ruling on performing ablution (wudu') and ritual bathing (ghusl) with Zamzam water?
It is permissible to perform ablution and ritual bathing with Zamzam water. However, scholars disliked using it for cleaning after relieving oneself (istinja'). And Allah the Almighty knows best.
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.