Doubt in Family Law

A", a Hindu and "B", a Christian married under Special Marriage Act, 1954. "A", proposed to adopt a girl child "C" one year old, who was his own sister's daughter and she was already having two daughters and "B" reluctantly agreed for it. post-adoption, B was very much particular that they should have a child of their own genes. Couple planned to have a child through surrogacy. "D" Boy child was born A, died in an accident. Grandfather filed a suit on behalf of his grand-daughter,"C" , for a share in "A" property in the District Court and for a declaration that D is not entitled to any share in his father's property as he is neither the natural or adopted son of "A". The court held that there was a valid adoption and the adopted child, "C", would be entitled to a share in A's property as "A" was entitled to adopt as per Hindu Adoptions and Maintenance Act, 1956 and his Christian wife's consent was irrelevant as per proviso to S.7 of the said Act. We have to file an appeal, challenging the validity of adoption. As marriage was performed under Special Marriage Act, 1954, Whether "A" had right of adoption under HAMA. Whether the consent of "Wife" necessary? there is no adoption deed. Whether "D" born through surrogacy has the same rights available to a natural born child. As marriage was performed under Special Marriage Act, 1954 the succession will be under Indian Succession Act as per sec 21. As Indian Succession Act, recognize consanguinity, whether adopted child has any right in the property? Any relevant citations will be helpful. Thanks in advance