I've been looking at the story's progress estimate here and I noticed that many characters already have their private arc almost complete or missing, because instead of posting new public arcs, making someone restart the game to play them doesn't end the routes right away. private and then only public ones remain?
For example, from what you understand Karlee is one of the ones that still needs to be completed in the private arc, so you could focus on her while moving forward with other characters.
Like, a person who has already completed private Aj would have to start over for the public and even then would have to have private Alex having to start over again later.
In this case, why not only advance the private routes until the end, for me it makes more sense that way.