A ruler's forgiveness of the loan as a way of dropping the deceased's debt

Q: Nasir ibn Muhammad Al-Quwayfily (may Allah be merciful to him) passed away. Amongst his estate were two shops that he left in his will as Waqfs (endowments) in Al-Kharj city. He said that the income from these two shops is to be spent on two Ud-hiyahs (sacrificial animals offered by non-pilgrims); one on behalf of his parents and his brother Sulayman; the other on the behalf of his wife, his children, and himself; and for someone to perform Hajj on his behalf. The remaining money should be given as Sadaqah (voluntary charity) during Ramadan to any of his children who are needy, and if there are none, then to (Part No. 16; Page No. 397) any of his relatives who are needy. If there are none of these, the Wakil (legally accountable person who acts on behalf of another for a specific permissible matter) has the right to exercise his own discretion regarding the remaining, as mentioned in the attached copy of the will.The question is: The income from these two shops exceeds the cost of Hajj and the two Ud-hiyahs, so what should we do with this surplus and how should it be disposed of? Should it be distributed to the deceased man’s children, the young ones and the adults according to their need or only among the young children? What is the criterion for the need, if it exceeds their need for clothing or food or other lawful expenditure? Should the money in excess of this be saved for them, for their future, as they are considered orphans? If so, should the boys and girls be treated equally in terms of their financial support as there are so many of them, or should the boys have twice that of the girls? Does his widow, the mother of the children, who still takes care of her children, have a share in this will, bearing in mind that she has not remarried so she can continue to look after the children’s best interests?It is worth mentioning here that the deceased’s daughters have waived their inheritance, as shown in the attached copy of the waiver, provided that their father’s debts are settled. Is this valid? Have they lost their right to inheritance and would this affect their right in the will if they were in need? Should the requested Hajj be repeated if there is still enough money or should it only be performed once? Among the estate was a house, built through the Real Estate Development Fund and his young children live there, but they were exempted from this loan. (Part No. 16; Page No. 398) Do the children have the right to inherit this house as the deceased submitted the exemption request in their names? Please advise us to free ourselves from this responsibility. May Allah guide you to what pleases Him!