1. IF Grand Father purchased the property in his own name with his own money, THEN the property CANNOT be classified as "Ancestral Property", for the relationships you mentioned. For a property to be classified as "ancestral property", such property documentarily should be atleast 4 generations old, which is not in the present case.
2. Grand Children have no right /claim on Grand Father's property, in anyway, whatsoever.
3. by virtue of above point no. 1, the Partitioned Property in name of Grand Mother, Father & Uncle, now will be classified as their own "self-acquired property" for all future legal purposes, including all future Sale /Transfer /Gift /Donate /Mortgage /whatever ....
Keep Smiling .... Hemant Agarwal