my opinion on your queries are as under:-
1) What is the best procedure to get this done?
Opinion:- immediately execute an agreement or settlement with her and file the mutual consent divorce before family court of area where both of were reside or where she is residing.
2) How much would it cost me and how long will it take?
Opinion:- cost is depend on the lawyer of your choice, and it will take six months time.
3) Also my wife is ready to give no objection certificate - will it be ok for me to get married to another girl legally?
Opinion:- no it is not legal, you may be prosecuted for an offence of Bigamy under section 494 of IPC.
What it means by finalizing the terms of mutual divorce?
Opinion:- it means on what terms and condition you both want divorce, like maintenance, stridhan, alimony, child custody if any. Withdrawal of cases or complaint or petition, future precautions,etc.
- How many times will we (me and my estranged wife) have to visit the court during this (A rough estimate is fine)?
Opinion:- 2-4 times within six months.
Feel free to call