Bigamy case

Dear Sir/Madam, I need legal advice on bigamy situation of my brother in law. My sister got married to my brother in law two years ago and they have one year old baby. But at the time of marriage my brother in law had first wife with two girl child from his first marriage. Couple of months ago, his first wife tried to kill my sister by putting poison in her food, but she failed even after four attempts. So, in village they called Panchayat and first wife agreed in front of many people that she tried to kill my sister. So, Panchayat took decision to send her back with two children to her parent´s house and with compensation of 8 lakhs rupees. But I am thinking to go for mutual consent divorce and make things clear for future. Now my question is, if first wife goes to police, according to Hindu marriage Act and criminal act IPC section 494, my brother in law has to go to jail for seven years or so. So, I want to know, if we provide her compensation and get mutual divorce, then when girls reach to maturity, do they have rights to claim the share from father´s property? And what are consequences if first wife files bigamy case on my brother in law? And what measure can be taken after filing case to get ride from this bigamy case? So please do answer my queries as soon as possible. Thank you. Govindraj Chavan emal id: