Does daughter have property share in Hindu undivided family

Hindu family: My father is the only son to My grandfather. and My Grandfather has a sister (no children) bought a house (with her earned money); and she wrote her will that, “the property must belong to my father (with all rights)”. My father first wife had 3 girl children’s, and he took divorce from his first wife; and married to the second wife (my mom). I am the only son to my father.My father was little sick, So he wrote his final will to inherit the property to me (with all rights); and it has been registered. But my three sisters (my father’s first wife children) threatening my father and me, that the property is ancestral property; and they get an equal share on it. 1) Does my dad' will is valid in this case? Does the property belong to me? 2) Do my sisters have right on the property, If yes, please explain? 3) If I start investing on the property, Do I face any future legal issue(s) with the property? 4) How the court final verdict would be, if they go to court? Please suggest,