One of our many cousins in Italy sent us some new information: the parents of Michele Galfre (born 20 June 1836 in Spinetta) are Giovanni Battista Bartolomeo Galfre and Teresa Dematteis. The parents of Francesca Manassero (born July 1839 in Spinetta) are Giovanni Manaserro and Teresa Cavallo.
This gives me some new names, dates and places to investigate, though I am not sure how much I will dig up from here. But at least when I do finally visit Italy (which shouldn't be too difficult from where I am!), I have a little bit more to go on there.