Im marrying a widow and how to deal with her previous problems?

Hello everyone my name is Harsh. Im 25 years old, single, unmarried. I have decided to get marry with a widow and my family also don't have any problem with that. Im well settled and earning good now. I got two proposals, both of them have some problems with in it. Please help me here to choose well bride for me. Case 1) she is 30 years old. She have a 4-5 years old son. Her husband committed suicide due to some debt. Now she is saying with her parents with her son. Her in law's against this marriage. Her husband take some loan for house purchasing. Her in laws denied her rights in that property. I talked with her. She ia currently working. And paying the installments of that loan. If I marry her, should I need to pay the debt? I talk her about her son, Im ready to take responsibility of him but I can't adopt him. I want to continue his father name. I also like to invest some money in mutual funds for his future. Will I able to do that, because he is not my true born son. Should his biological grandparents give his mother some money to help her to raise him? Case 2) she is 31_32 years old. She have a daughter. I haven't met her yet. She lost her husband due to some illness. Her husband also have some debt. Here too I need to pay her debt if I marry her? Her inlaws are not against this marriage but they aren't willing to give the custody of the child to mother. After her husbands death her daughter is living with her fathers parents. They refused to give her daughter back whether she stays widow or get married. What should I do to.get her daughter back to her.