Does the clipping of nails nullify ablution?
No, it does not, and it is preferable to wash the hands afterwards.
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.
Is it permissible for a woman to shake hands with her brother-in-law?
It is forbidden for the woman to shake hands with her brother-in-law because he isn`t a Mahram (unmarriageable) of hers.
If the menses lasted for over than 9 to 10 days, considered menstruation?
If the duration of the bleeding does not exceed fifteen days, it is all considered menstruation, even if the usual pattern changes.