So Owen with scarf if the young Owen then? Since main Owen gone back to past to stop grey Owen so now young Owen and main Owen and grey Owen are not in one universe?
No, there are five Owens. They are all individuals but share a connection with the Main Owen and share thoughts with each other. Slight spoiler for the next chapter, but two Owens are showing up. So, this means they can exist in the same place.
So Owen with scarf if the young Owen then? Since main Owen gone back to past to stop grey Owen so now young Owen and main Owen and grey Owen are not in one universe?