1) deed of adoption can be executed In Vadodra wherein you are residing permanently with your child and step mother
2) Clause 4.4 of the Passport Manual, which reads as follows:-
"4.4 In the case of (b) above, the name of stepfather/stepmother cannot be written in the passport of children from the previous marriage. The relationship of the child to his biological parents subsists, even after divorce by parents. In such cases, the column of father or mother in the passport cannot also be left blank. Therefore, such applicants must apply with the names of their biological parents. However, if the stepfather or stepmother is appointed by a Court as legal guardian, the name of such a step-parent can be written as legal guardian."
3) para 4(III) of Chapter 8 of the Passport Manual, which permitted the parties to have the name of the biological parent replaced by the name of the step-parent, in the event of death of the biological parent.
4) Wherever there is a valid adoption, which satisfies the requirement of the Hindu Adoption and Maintenance Act Act, 1956, there would be no difficulty in replacing the name of the biological parents with that of the adoptive parents in the passport