Regarding these murders -
From the article in the Times Picayune I referred to earlier, it appeared Benedetto Giordano was the son of Rosario. I found a Times Picayune article on the trial of the murderer, dated 13 Jun 1899, and the Benedetto referred to in the previous article was an overseer on the plantation. Rosario's murdered baby was referred to in the trial as "Pepino" I believe. His murdered wife was referred to as "Rosalia", and his daughter, who was shot by the murderer but survived, testified during the trial and identified the man who had shot them.