Is it permissible to make ablution without answering the call of nature after waking up?
Washing front and back openings (Istinjaa`) is not a condition for the validity of ablution because it is done to remove Najaasah (impurity), thus if there is no Najaasah, there is no need for that, and then it is permissible to make ablution without answering the call of nature. However, prayer is invalidated if there is Najaasah on the anus ,or the front opening, so it (Najaasah) must be removed for the prayer to become valid, and not the ablution.
How does one with a continuous condition (like urinary incontinence or non-menstrual vaginal bleeding - mustahada) perform ablution?
A person with a continuous condition must do three things:
1. Not perform ablution except after the prayer time has entered.
2. Change the bag or diaper placed to reduce the flow of urine or blood after the prayer time enters, wash the private part from blood or urine, and perform ablution immediately.
3. Perform the actions of ablution in immediate succession, then pray immediately without delay, unless he intends to pray with the congregation.
It is not permissible for a person with a continuous condition to combine two obligatory prayers with one ablution, as he must perform ablution for each obligatory prayer, even if making it up (qada'). And Allah the Almighty knows best.
What is the ruling on the ablution of one who touches women prohibited to him by a temporary prohibition (mahram bi-hurma mu'aqqata)?
It is prohibited to touch a woman who is temporarily prohibited (meaning one whom it becomes permissible to marry after the impediment is removed, such as the wife of a brother or paternal uncle). Touching her without a barrier invalidates ablution. And Allah the Almighty knows best.
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.