The relationships among the characters in Bodas de sangre do not correspond to those in the "original events."
Leonardo is married, with a child, and mother-in-law living with them. His wife is a cousin of the nova.
The Novia is an only child.
In the original crime, the Novia's sister and brother-in-law are the ones committing the attack, not her fiancee, who is not killed.
The cousin the Novia escapes with is not married.
Literally, every family relation is different in the play, and, I would argue, it is a play about such relations.