Wasiyyah (Bequests)

Q: My parents married out of community of property, but jointly owned a house. My mother passed away before my father. Mother left no will. My father made an Islamic will. He also typed on a separate letter that half of his share of the house goes to his divorced daughter after he passes away. He passed away leaving 5 children i.e 1 married son, 3 married daughters and 1 divorced daughter. Some are complaining that the separate letter defeats the Islamic object of the will. Please advise.

Q: I would like to know if the marhoom used to say that when he passes away, a certain property must go to his grandsons, then is this a wasiyyat. The grandsons are not heirs.

Q: A lady passes away she leaves behind four children two sons and two daughters and a husband, after she passes away it is realised that she has some money in the bank,so after her demise the husband states that during her lifetime she told one person that if she passes away her husband should use the money for haj, I would like to know is one persons statement sufficient to prove that that she really said this and two what is the manner of fulfilling the bequest of the deceased according to shariah?

Q: Can a person make a wasiyyat for a murtad and if he makes one does it have to be fulfilled?

Q: We have only one daughter. According to the Shariah the distribution of property in inheritance after one passes away says she receives half of her father's wealth. However we want to bequeath the other half of the wealth to her as a gift after our demise. Is it permissible?