1. Mr Shivaji's share would devolve on Mr Baidnath which would be equally divided among his legal heirs.
2. Yes, he can do so.
3. All the co-sharers can execute nd register a mutual deed of aprtition. Similarly one can get decree of partition on compromise from the local civil court.
4. He can do so. However to premept such attemot, you can file parittion suit and for injunction.