Adding as confirming party or consenting withness

Dear All, I have recently entered into an sale agreement for an plot in Bangalore. Where in the owner(PARTY A) has asked an builder to develop his land of 4 acres into an layout. As part of this development the builder(PARTY C) has registered an agreement with owner to sell few plots which he has mentioned as development fee to the builder. As well the builder has investment amount for the same. 1. My plot is part of the portion where builder has Right to Sell(registered with 20k) as per the agreement document. 2. I have carried out an sale agreement with the owner and an assignment agreement with builder.Is this ok? 3. Earlier we had prepared an draft SALE DEED mentioning Party C(Builder) as CONSENTING WITNESS as part of the loan authorities requirement we had to modify Party C(Builder) as CONFIRMING PARTY is this OK ? Do we need to keep the Party C(builder) as CONSENTING WITNESS or COMFIRMING PARTY? 4. Do i need to raise an agreement to cancel or nullify the Right To Sell of Party C(Builder)? 5. Any pros and cons . Any suggestion on how to proceed with the deal? 6. Can the confirming parties immediate relation can raise an claim later? 7. Will adding the builder(PARTY C)CONFIRMING PARTY remove all his rights to the property? Thanks Raju