There's a character who's not explicitly stated as gay but could be read as lgbt (their relationship to a same-sex protagonist is obsessive to an extreme), and she lives sad and lonely (and is cast out by someone else) due to her obsession, and dies in a sad kind of way.
The main character Esteban Garcia is frequently violent with his temper, but only in later chapters is shown to be abusive to his wife and daughter. (hitting his wife and whipping his daughter)
not closely related enough to be incest, but a horrible character (illegitimate son of /person/) rapes (legitimate granddaughter of /person/, and groped her when she was a child)