I have a recent one! I was wondering where to put it when I found this thread. Sorry if this was theorised before or common knowledge, couldn't keep up with the fandom for a while.
So, I too, belive the Chi Maleficient is the real one, but I belive the ED UX version is not. Also I belive Chi and Unchained X are less connected, or connected in a different way.
We know the story bits with the new Union Leaders are flashbacks to before Unchained started, correct?
We know Maleficient knows about the Book of Prophecies and the black box, also we know she entered the datascape during Coded.
We know that Sleeping Worlds are doomed to repeat what happened before their fall, right?
Based on these I came up with this:
The world where Chi takes place is the digitalized version of a Book of Prophecies Maleficient found. Exactly like Mickey digitalized the Journals. At the end of Chi, we see her enter the digital world, but I assume she kept watching all along the story. This also includes Back Cover, and spying on the digitalized conversations of the MoM is how she knows about the box. But of course she doesn't know what's in it, because the 'recording' started after he closed it. The MoM might even knew he will be spied on like this and his "Suprise" line was actually directed at the voyeur, teasing her, rather than to Luxu. I wouldn't be suprised if the box turns out to contain a trap or a joke.
Ephmer realised the worlds were just projected in Chi, but he didn't realise even Daybreak Town and himself were just data. When he did, he became 'Unchained', as Ava said. I think it means overcoming the system, like Data Sora did when he got a real keyblade. This is also how he can be relevant in KHIII or post-KHIII, making contact through the datascape.
Now, Unchained Chi is actually the continuation of the story that Chi was based on, instead of Chi's continuation.
I mean, timeline wise: Fortellers, Unions, Dandelions, War and stuff happens ---> Unchained Chi --> present time --> Chi
Unchained Chi takes place in the Realm of Sleep. The war at the end made Daybreak Town fall into darkness and it ended up in the Realm of Sleep. That's why we have pets (Spirits) in UX, they can't properly exist in Chi, a simulation of a world outside of RoS. (Chirity doesn't count, he can't even eat nightmares.) Maybe the kids MoM choose to be Union Leaders all have the potentional to overcome the system (not just digital systems, but rules of the sleeping worlds.) Something bad will happen at the end of UX and Ven and Laurie will be thrown out of the Realm of Sleep, ending up in a close-to-BBS time without memories.
TL;DR: if you didn't play Chi, just watched the cutscenes along with Back Cover, you are Maleficient, also UX is more like a pre-sequel to Chi taking place in the Realm of Sleep.
