This does seem really neat. I LOVE the idea!
I do wonder about the original intent. Don't see how a 25 year-old-couple died together romantic though that might seem.
But these Italians! They take romance to a new level!
My wife and I have talked about a similar burial for us, but we decided that since we may not go at the same time, a good alternative would be individual cremation and then mix the ashes when the second one goes.
Some cultures it was common to bury animals, retainers, servants, even living spouses with a dignitary so they would have company and support in the afterlife. Just read about a noble woman in Peru who was found with a servant girl buried next to her. A strangulation cord around the girl's neck.
Though things like this may seem gruesome and macabre to us, it was often an act of love and devotion in these cultures.