Please excuse me for not answering your questions in the morning in much detail as I was in the courtroom. However, below is a more detailed reply to your questions:
1. Your first question stating that marriage and registration took place in CA, and later on it was performed as per Hindu Rites in 2010. In view of this, the judgment passed by Hon’ble Madras High Court in "Bhashyam Ramesh @ Rajagopalan vs R.Saroja @ K.K.Saroja on 24 February, 2012" stated the rule that "Thus, it is clear that only that Court will be a Court of competent jurisdiction which the Act or the law under which the parties are married recognises as a Court of competent jurisdiction to entertain the matrimonial dispute. Any other Court should be held to be a Court without jurisdiction unless both parties voluntarily and unconditionally subject themselves to the jurisdiction of that Court.
2. Therefore, based on the judgment above if both, your son and his wife accept the divorce of the court in CA, then the divorce is valid and no further action is required. In Indian context, further judgment of divorce from family court is not required though if the situation demands that both of you would be comfortable if the divorce order be secured from family court in India, then a simple application for mutual consent under Section 13B of the Hindu Marriage Act to dissolve the marriage as per Hindu law would suffice. However, when filing for mutual consent the judgment of divorce from CA must be attached to expedite the matter quickly within few months. If the judge is convinced within a date or two the court might pass the order for divorce by mutual consent. And, for filing mutual consent, you may require lawyer, albeit not necessary.
3. Question (C). Even currently, if both parties have agreed and accepted the divorce from the Court in CA without disputing it, then your son is free to enter into any matrimonial relationship of his choice.
4. For returning the jewelry, please prepare a list of articles received at the time of marriage. And with due consent from girls side, please handover the articles. However, please DO NOT forget to take the signature/s from the girl’s side, in the presence of two witnesses upon the delivery of the articles to the girl. Alternatively, you may also request them to collect the articles from your residence apart from jewelry. The paper mentioning list of articles should state that "We have received all the articles given at the time of the marriage and have no further demand, nor shall have any claim in present or in future”. This could be done on a simple paper prepared in duplicate wherein one copy shall be given to the girl and the other would be required to be retained by you. It is not mandatory to prepare it on a stamp paper, but if you may prefer, purchase two Rs.100 stamp paper in the name of your son and do as suggested in the sentence mentioned hereinabove.
5. Question (E). There are no other formalities, nor any lawyer required to execute the same.
Hope I answered your questions. Please touch base with me should there be any further clarification required.