• Sanctity of development and family settlement agreement

My father and his siblings in all are 6 brothers and 2 sisters including him. We have ancestral lands, where we have planned a township and made a ratio deal with developer and has provided him 35% plots against development of township and 65% to land owners. The land has is divided 5 kasras, where three has joint name of all siblings and 1 khasra of land has name of 2 brothers, and 1 khasra in one brother name

Now, the eldest brother of my father is of bad mind and has always tried to make some or the other hurdle for the project. His name is only on joint khasras and not Individual khasras. He didn't wished to share the land with anyone and wished to show it to concerned authorities as his own by collecting some farming bills since last 8-10years. With very difficulties he got ready for doing a project on the land. He needs extra amount of plots for which he blackmailed us for years, and being the eldest no one raises there voice.

 Finally A development agreement was prepared between land owners and developers in 2012, which shows division of plots among developer and land owner and further it also shows division of plots among land owners also, and was signed by all siblings of my father except the eldest one in 2012.

Finally the eldest one signed in 2015 on the main development agreement after attaching a supplemental deed to original one where all brothers have agreed to provide him extra plots and all siblings signed that too on the same date as of original agreement. The settlement was done by 50 percent plots from developer and 50 percent plots from all land onwers  of the eldest brother total requirement.

Now, the main agreement with supplemental deed was sent for registration  but only main agreement came out from registrar office. On asking the developer for supplemental deed they said that its stamp duty is yet to be paid so it didn't got registered. The sign was done in march 2015 and registered in April 2015.

Now the next part is, the main agreement got registered and stamp duty paid keeping one thing in mind that all the parties to agreement should get indigenously, title, possession and right to transfer there indigenous plots going forward, and the lawyer of developer says  that the developer and all individual land owners can do registry in there name without any other party sign required. No my doubts and  questions are:

1. Is that division of plots among the developer and land owners and further among the land owners valid in the eyes of law and they can do individual registry in their names. That all siblings have got title, possession, and right to transfer the no. Of plots shown in main agreement and can do the same as and when they want with their individual signatures only?
2. The eldest brother goes to registrar office saying that the main agreement is under stamped and threatens us again. So I checked it from lawyer and he said that the stamp duty of 35% of developer land is been paid and among family its not required and I assure you that your registry will be done by your father individually. So is that safe and sound step even 10 years ahead(considering any adjustment was made with the registrar by developer)?
3. If th eldest uncle succeeds in making his point of under stamping and sends notice to us and the developer, but at that time registries of individual plots done by developer and other brothers and sisters is done, then what will happen to these registries?
4. All brothers have distributed equally the share of plots among themselves including the eldest brother and decided to give a specific amount fo share to sisters with their consent in the main agreement and all have signed on the development cum family settlement agreement. So in that event what point can he prove or gain by sending notices to us and developer, and will he succeed in jamming the project by any manner?

Kindly answer these questions and any other inputs from your side to keep in mind to safe guard everyone's interest.