Rights of Second Wife and her kids in property

Hello, My father-in-law has expired a few weeks ago and he was married to two women. Father-in-law: # Did not write any will for the properties # His bank accounts nominee is first wife's three children # His nominee for the pension is second wife First wife: # He had married his first wife in 1990 and they had three children. # All the earned properties (land, house, etc..) were equallly divided and registered to both of them # Both of them started living separately since 2012 # First wife died in 2018 # Death certificate was prepared with my father-in law's name as husband's name. # The legal heir of the first wife's property was made in the name of my father-in-law and his three kids from the first wife. Second wife: # He had married his second wife in 2015 and his second wife had one kid who was not born from my father-in-law # Second wife and the kid who was not born from my father in law have prepared the death certificate of my father-in-law with Spouse's name as second wife's name. Question: # Who is legally the primary owner of all his properties? # Whose name is legally eligible in legal heir? # Is the second wife and her daughter who was not born from my father-in-law are legally eligible for a share in the property or she is the 100% heir of the property? # Is it illegal to prepare legal heir with only first wife's children names? # If second wife's name is to be included in the legal heir, should the second wife's daughter(minor) name also be included? Request you to please shed light on these issues. Thanks in advance!!!