Property selling when one person is minor
I have some queries regarding my property. My father had purchased land in Delhi around 125 sq. yards in the year 1985. This land was purchased in the name of we, three brothers. My father also built ground floor of the house. After some years my both brothers died. They have left families having children. Now we want to sell that property. My elder brother has three children two sons and one daughter, all are above 18 years and married. My younger brother has two children, one daughter and one son. Daughter is 18 years but son is 15 years old. As we are three co-owners of the property, we decided that one will take the back portion and two will take the front portion of the property. The following questions now arise :
(1) whether we have to make a family agreement to sell the property?
(2) Whether this agreement would be registered and with whom it would be registered sub-registrar or SDM?
(3) Whether all the children have to make relinquish deed in the favour of their mothers?
(4) Whether these deeds would also be got registered with sub registrar or SDM?
(5) As one child is below 18 years, I think the relinquish deed made by him may not be correct, then what should be done?
(6) Whether his mother as guardian can take decision on his part?
(7) If we sold the property now, whether the minor child can create problem after becoming major.
I shall be grateful if the reply to the above questions may be given urgently.