Urgent help required in false 498a and child custody case

Hi all, I have been married for 10 years and have a 4 year old son from the matrimony. My wife was living with me without any issues for last 8 years but started creating problems as soon as my parents moved in with me after their retirement a couple of years back. For the last couple of years she was forcing me to stay away from my parents and started creating public scenes frequently. Every time I tried to counsel her and things seemed to get back to normal. However in October 2014, me, my parents and my son had gone on a 3 day vacation which she refused to join giving reasons of some critical office work On returning back from the vacation I found that she had left our home and had taken all household stuff and kids clothes/toys with her. Me and my parents called her and her father but were given threats that we had tortured her and they had evidence about the same (false threats) Given the route which they were taking, I got scared that they might file false cases against me and my family and left with my parents and son to my parents home at Delhi. Later I again contacted her via some friends and with their mediation we agreed to come up with a MOU which takes care of both our concerns so that we can lead our lives peacefully in the future. The Mou was discussed and is in mails but I never forced her to sign the same Meanwhile My wife lost her job and came back to me in Delhi . She was ok for a month or so but again started misbehaving with my parents and making a mountain out of every small issue. Then one day she said she has got a new job in Bangalore and went ahead and joined that leaving the son in my care. She used to visit me and our kid once in 2 weeks. On April 20th she visited my home with the pretext of celebrating Holi with the family, however she kidnapped or child and ran away while we were all sleeping . I immediately filled a police complaint regarding the same in my city. Later on I have been informed that she has filed a FIR with 498a, 503, 504, 323 and 3/4 dp act in Agra against me and my entire family. I have been attending mediation sessions for almost 4 months now but finally the mediation failed as she and her family were trying to blackmail me into submission by providing her child custody for life, transfer 1 house to her name and 1 on child's name, move to a location where she has a job etc She works for a multinational and earns almost same as I do. Please help me by guiding me on the following questions ?? 1. How can I ensure that I can get my sons custody . Everyone I talk to tells me that I can't get the custody as my son is only 4 yrs old. I asked for joint custody during mediation but my wife refused the same 2. Will getting the physical custody back of my child help in any case specially with false harrasment cases filed against me. He was under my care till April, 2015 till my wife took him away 3. came to know that my wife was under treatment for depression for last 3 years ...will this help me in any way? 4. what chances I have to the get the fir quashed on basis of jurisdiction, given there is no cause of action in Agra except that our marriage was solemnised there. The FIR also mentions any cognizable offence in Agra. 5. My sister and brother in laws name has been causally mentioned in the fir without specifying any date or specific event. Will quashing of fir be easy for them ? 6. Also will the fact that I immediately filed a police complaint on the day she took my son away help my cause in anyway ? Please help me as I am getting no credible answers from my lawyers and really looking for some practical and actionable advice from this forum of experts: Thanks