Partition Deed

Sir My father died in 1998 and mother died in 2008. We are 2 brothers and 3 sisters. He left a unregistered will duly witnessed by one of my sister (No 2 daughter), bequeathing his immovable property in New Delhi to his 2 sons equally and movable property to be equally shared among daughters.His wishes were carried out . The sisters have given a Notarised NOC and a affidavit stating therein to relinquish their right on the property and have No Objection to mutation of property in favour of the 2 brothers. The Mutation with MCD records have been completed. The will has not been registered or probated. Now 2 brothers (50% share each as per will) want to enter into a partition deed based on the will of father and further re-develop the property through a reputed builder collaboration, giving builder 22.5% share in undivided property. Balance 77.5% to be retained by 2 brothers. Please advice: 1. will there be a problem/difficulty faced while registering the property in favor of builder or his nominee ? 2. The partition Deed between brothers needs to be registered before hand ? 3. Are presence/signature of the sisters required as they have already given a NOC and a affidavit stating their intent to relinquish their right on the property at the time of registration of sale deed subsequently on completion of redevelopment of property thank you HS