Salt Lake, Kolkata

Hi, I am a resident of Salt Lake, Kolkata and my father recently passed away and is survived by my mother and myself. I am seeking advice on how to transfer the rights of the apartment (basically sell the apartment) of which he is the bearer of 1/3 rights of the plot and the entire apartment. He had entered into an arrangement with the plot leaseholder to inherit the rights of the apartment upon failure on part of the leaseholder to repay a certain loan my father had made to him. I am aware that such an agreement will have to be established again with the new transacting party as buying/selling is prohibited in Salt Lake. My questions specifically are: 1. Who inherits the property after my father's demise, is it my mother or myself? 2. Can we set-up a new agreement directly with the buyer or do we need to FIRST transfer the ownership under us before proceeding to enter into an arrangement with the eventual buyer? 3. Do I need to contact the leaseholder who has acquitted himself of the rights to the apartment and 1/3 share to begin with? Does that person need to be involved in the transaction? Many thanks.