1. & 2. You shall have to sign the Deed before the Registrar while registering the same for which you shall have to travel to Pune,
3. You mentioned "After my father death , the plot was transferred to my mother name. My mother was nominee and she transferred plot to my brother". How was the property transferred in favour of your mother? Was there any Deed or will in favour of your mother conveying the title of the property in her name? If not then she also shall have to execute and register the relinquishment deed,
4.No. Once you execute and register the relinquishment deed, you relinquish your claim on the property for ever,
5.& 6.Registration charge varies from state to state and yu can find it out from your local registration office,
7.Engage a lawyer who will draft a Relinquishment Deed which you shall have to execute and register before the Registrar at Pune,
8.Yes, but he shall have to get it registered before the local Indian Consulate. Without registration no deed of conveyance is valid as per Indian Registration Act,
9.If the deeds are registered then the ownerships will be absolute.