Spoiler:
I came to this same conclusion as well. Even TJ recognizes Flynn as Plug face (having no other name...) What has me confused is Sam's attitude depending on the route. Sometimes he just helps and sometimes just lets Chase to rot, outright abandoning him and condemning him to the transform Flynn into...that. For this I believe that "the other" from Adastra series is the Evil of Echo. And sometimes Sam is overtaken by it and sometimes just helping the otter