Is it permissible for someone who has forgotten to mention the supplication pertaining to answering the call of nature to say it while in the toilet?
It is disliked for a Muslim to mention Allah while in the toilet, but he/she may recall the supplication in his/her head without uttering it; that is in case he/she had forgotten mentioning it before entering the toilet.
Is it permissible for a woman to offer the obligatory prayer after Adhaan (call for prayer), and before Iqamah (The announcement that the prayer is about to begin) in the mosque?
Yes, it is permissible for a woman to offer the obligatory prayer immediately after the Adhan and before the Iqamah in the mosque. And Allah Knows Best.
If the fasting of nine years has accumulated upon me, I wish to make them up by dividing them over several years, as it is difficult to fast them all in one year due to their large number. Consequently, expiation will be due on me. Is it permissible to pay the expiation after completing all the make-up fasts, even if it takes years?
If the fasting was broken due to a valid legal excuse, it is permissible to divide the make-up fasts over several years based on one’s ability. However, if a person passes away before completing the make-up fasts, the heirs must fast on their behalf or feed one needy person for each missed day.
If the fasting was broken without a valid excuse, one must hasten to make it up. Should the person die before completing the make-up fasts, the heirs must either fast or feed the needy on their behalf. As for the expiation, it is calculated after completing all the make-up fasts. And Allah Knows Best.
Is the father a Mahram (Non-marriageable) to his son`s mother-in-law?
The father is a non-Mahram (Marriageable) to his son`s mother-in-law, so it is impermissible for them to look at each other, or to have a seclusion (Khalwah).