Is it mandatory to include legal heirs in GPA document

I am planning to buy an under construction property in bangalore. This is a joint development project. The builders and Land owners have signed a Joint development agreement (JDA), general power of attorney (GPA) document in favor of the builders, giving the right to build the apartments and sell them. In the JDA the builders have included the legal heirs of the owners of the land. Say X is the owner and Y is wife, and A, B, C are the legal heirs(children). So JDA states that the owner X and Y agree to construct residential apartments jointly with the builders. The legal heirs A, B and C have given consent by signing the document. This property has been inherited by X from his father through a partition deed. He has then gifted a part of the property to his wife Y and it is registered in a gift deed. So ,the owners of the land are both X and Y. The GPA, executed on the same day, states that X and his wife Y are the owners(first party) of the land empowering the builders with the right to construct and sell the apartments built on the land. The agreement does not include the legal heirs A,B,C. 1. Should the legal heirs be included as parties in the GPA? 2. Is there any legal impact of not including the legal heirs in the GPA? 3. Since the JDA and GPA have been executed on the same day, does it imply that the legal hiers have given consent for Power of Attorney also? The builder is saying that legal heirs are not mandatory in GPA. And they have given their consent in JDA. Could you please let us know the legal impact of this ? Please advice us if we can go ahead with the purchase ?