Wife not coming back from her parent's house

Hello sir, My mother in law take my wife and my new born child from my house six month before for rest after delivery but now they are not sending back my wife and my child. They are blackmailing me to sign on stamp paper for many conditions which they want to fulfill. I am a govt employee. My mother in law clearly said that sign on stamp paper or live lonely whole life and if I try to go to court, she would teach me lesson. I tried my all efforts to bring my wife back but all in vain. I take help of elders of my family as well as her family but she (mother in law) send out of house to them. My mother in law interfering in my home since first day of marriage. She educate her daughter (my wife) to record all small things while we are together, even I don't know about this. So sir they left only two options for me ie: either accept their demands (which may increase in future) or live lonely whole life. Sir please guide me in this case. I think if I file section 9, they either counter file 498a or they make many allegations like DV or etc and hold this RCR for years. I think it is waste of my time. So pls help me in following questions: 1- Can I file RCR first? 2- Can I file divorce directly? 3- Pls suggest best family lawyer in Ajmer (Rajasthan) whose success rate is very high. 4- Can I seek child custoudy during RCR? 5-What loss would be to me in these case, I am a government employee, and pls suggest precautions?