I have come across your relatives' names many times while searching for mine. Your Maria Giuseppa Iacobucci fits roughly into the time frame as my gr-grandpa, who was born in 1888 and his brother in 1886. They did have a brother and a sister who remained in Italy that no one seems to know their names. I only know that they existed because of being listed in obituaries here as "a brother and sister in Italy."
I know that my grandfather lived in San Valentino, Pescara (then Chieti), Abruzzo at the time of his marriage. However, my dad said that he was from a town/village further north. His parents' names were Carmine Giuseppe Iaocbucci. His mother's name was Elisabetta Marchetti. I cannot find a lot of information on either one of them in San Valentino, so maybe they moved there as opposed to being born and raised there.
In the last few months, I have come into contact with a man via a post on an Italian genealogy website, who happens to be my third cousin once removed. My ggg-grandmother and his gg-grandmother were sisters (DiSanctis from Alanno, Pescara, Abruzzo). We have been writing ever since and filling in huge gaps in each other's family trees. So, you just never know. Even if we are very distantly related, it may eventually lead to making the Iacobucci tree much fuller! =)
Laurie