The first question will have two answers depending on whether the second marriage took place pre-1955 or post-1955, since it is after that only that bigamous marriage (two wives of the same husband) is void in India.
Pre-1955: The property will be divided into four shares leaving the shares of the 2 sons who got separated. The two widows will share 50% each from one of the four shares. The other three shares, will go to the 3 children of the second wife.
Post-1955: The property will again be divided into four shares, however this time the second wife will not get any share, by virtue of the second marriage being void. The first wife along with the 3 children of the second wife, will get one share each. It is interesting to note that even when the wife of the void marriage does not inherit, the children from that marriage can inherit their father’s property, because they have been legitimized by virtue of Section 16 of the Hindu Marriage Act, 1955.
The second wife will however have no right on the second wife’s property, since her sons are alive, who will inherit the property. In case they are not alive, the wife’s property will devolve in the same manner as that of the husband.