What if Padme Amidala had an otherwise unmentioned younger sister?
She would naturally hate the Empire, since the second in command of the Empire killed her sister. So she would quite reasonably want to help the Rebels fight against the Empire. In other words, she could be Jyn Erso in Rogue One.
Maybe she fades into the background after that, and after the events of Star Wars – RotJ she settles down, has a daughter, and then gets her cover blown and has to abandon her daughter to protect her. In other words, she could be Rey’s mother.
This would explain why the characters played by Natalie Portman, Daisy Ridley and Felicity Jones all look alike. It would also explain why there seems to be some sort of family connection between Rey and the Skywalker/Solo clan – she’s Luke and Leia’s first cousin, once removed, and Ben/Kylo’s second cousin.