Hermione travels back in time knowingly and instead of creating a new timeline she alters her original one. Enter new Hermione in the same universe, same characters and the same old Hogwarts and chaos ensues (well not really)
Merope Gaunt never bewitched Riddle, rather her granddaughter was swept off her feet by the Charming Riddle heir. Thus the Slytherin's heir was born, Tom Gaunt-Riddle, 1897. 3 years later the Grangers birthed their daughter, the heir of the Raven not by blood but by magic,the strongest bond. A Prophecy made several years before entertwined their fates in a unique way. Tomione