Hahaha I'm definitely not ruling out any kind of extra AU chapter once the main game is all finished and released, but I've not put that much thought into the specifics of what kind of setting that would be, or how much similarity that would have to the main game. It's always an option, though!
(I think being somewhat of an AU would help reconcile it with the themes of the main game itself - whereas I'm not as eager to write something that subverts the events of what is otherwise the same story/setting. But this is all extremely conceptual right now, so I can't say either way~)
I'm glad you're enjoying the characters that much though! ^^ A couple of people have asked for something like this now. I'll put serious thought into what kind of nicer (though emphatically bonus) content I may potentially want to work on at some point in the future!