There is no original anymore. Remember the X-men issue where sinister made an entire city of himself to fight the Phoenix? He is just dna and recorded memories. There is no “him” anymore. It’s why it doesn’t matter which sinister went with the team. They even have greycow foreshadowing it by saying the empath he killed and the empath reborn are not the same person. But nobody can notice so who cares? (Not getting into the resurrection stuff. That’s just magic) so the book is telling you. Don’t worry about which sinister was chosen just know that sinister will still be in the book no matter what