What were the surprises encountered by these beneficiaries as they gathered?

When E.J. Plum begins the reading of the will, he reminds the group that he has never met Sam Westing. The FIRST section of the will claims that each person in the racially diverse crowd is one of his 16 nieces and nephews, which causes outrage from Grace Windsor Wexler. The SECOND part claims that Sam Wexler was murdered by someone in the room, causing another outcry.