Tranfering property from GPA

Good Morning Sir I want to know some information from you regarding our small commercial booth and will be very grateful to you if you provide me information regarding the same. My father bought a small commercial Booth in Chandigarh 20 years back from allotee and it was on general power of attorney till date. Due to financial circumstances, he will not be able to register this booth on his name and still running on allotee name. My father expired two month back and now we want to make this booth transfer on all of my brothers and sister (four) name. We also have WILL on legal paper stamped by Sub Registrar, given by allotee at the time of selling his booth. According to this will, he has gifted this booth to my father and his family will not claim any ownership on this booth in future after allotee death and if my father expire before him then we have full right to transfer this booth on our name. Now my questions are 1. Is allotee or any of his family member has any right to create issue on this booth as we have registered general power of attorney on my father name? 2. Is allotee’s presence necessary during registration of property in our name? As we have not any idea about allotee whereabouts in all these years. 3. Is this property directly transfer in our siblings name or first we have to transfer in our father’s name? Thanks and Regards Pooja Sharma Chandigarh