Property Claim

Respected Sir / Madam, My elder sister got married 10 years ago. My father gave her some gold ornaments and a plot of Rs. 2.5 lakh. But, as the plot had problems for constructing house, he again gave my brother-in law Rs. 5 lakh (as a debt) to buy another plot. My sister got death by a byke-tractor accident just after 1 month of constucting new house on the 2nd plot. My brother-in law was driving the byke. They has a daughter of 5 years age. After 1 year of her death anniversary, my brother-in law is planning to marry again with another woman who is a divorcee with one son. Now, my questions are- 1. Is it possible to make my niece owner of 1st plot and in absence of her, ownership will be on our hands ? 2. If the plot can be sold, Is it possible to fixed the amount in the name of her and in absence of her, it will be on our hands ? 3. Is it possible to make my niece owner of the Gold Ornaments and in absence of her, ownership will be on our hands ? 4. How to get back the amount of Rs. 5 lakh what my brother-in law once assured my father to return back? This is under West Bengal jurisdiction. Please tell me some solutions. Thank you.