Sailor Nothing/WMG

Ohta is in love with Cobalt
There's a serious Burns-Smithers vibe between those two. The devotion and concern, in a race founded on cruelty, torment, and backstabbing? The way Ohta keeps running to Cobalt like a little puppy dog? Come on! If this is a deconstruction of Sailor Moon more than any of the other Mahou Shojo shows, why wouldn't there be analogues to Zoicite and Kunzite? Plus, there's a villain named Cobalt in the anime series Iczer One, and she's the first villain the heroine kills, a high-ranking officer of the enemy whose death moves her lover Sepia to take up the battle in her place out of grief. However,
 * As an offshoot of this theory...

The human version of Ohta is bi-curious, but can't act on it; his Yamiko counterpart was free to seek the love of a man.
What do Yamiko do? Act on their template's bottled-up desires and impulses. They are id incarnate. But even after, there would have been nothing stopping Yamiko Ohta from seeing a male lover. His human counterpart had a wife and children, yes, but the yamiko was single.

"Magic" still exists
The properties of the universe that allowed logically still exist. Therefore, there's no reason such things would be physically impossible in other circumstances. Given enough time and enough people, it's likely that someone will do something with magical results.
 * As further speculation, discovered, way ahead of time, things that are usually discovered as part of Magic From Technology. This may open up fanfic Crossover possibilities. (Would Nanoha be feasible?)
 * The thought of the Sorting Algorithm of Evil kicking in in the Sailor Nothingverse is too terrible to contemplate. What would a creature formed of pure Super-Ego be like?
 * Darkseid?
 * Without the constraints that living in The DCU places on how he uses his powers? We're back to "too terrible to contemplate".
 * Superego personified would be ruthless hardcore Knight Templar. That is something to consider.

Aki is not a lesbian, but a Deconstruction of Everyone Is Gay and the common fan fallacy of seeing all forms of love as only sexual.
So she deeply loved Himei. The Greeks had different words for romantic love (eros) and friendship (philia). It's entirely possible for Aki to love Himei in a deep, profound, non-sexual way. It's likely that this Magical Girl Deconstruction would show how messed up the incapability of loving in any way but sexual would make people. The thought that her feelings must be romantic deeply distressed Aki. Her not being truly lesbian would also account for her relationship with a girlfriend in the Where Are They Now Epilogue being on the rocks.
 * What about agape?
 * If they can't imagine friendship as a deep and serious love, how will they ever get agape?!

Sailor Nothing leads into Kingdom Hearts.
For the full explanation, see its entry on the Kingdom Hearts page.

Sailor Nothing takes place in the same universe as The World Ends With You
Yamiko are created by fusing the Noise surrounding a person together. (In the case of Super Yamiko, the Noise are first converted to Taboo Noise). This process removes their ability to exist in two places at once, but it also reduces their vulnerability to living beings. The Yamigaia is simply a plane with a lower vibe then the Realground; thus, the blocking powder simply disables the Yamiko's ability to alter its vibe. Furthermore, the purification ritual the priestess used had been planted by a fallen angel.

Yamiko are sapient Unversed, akin to Vanitas
I'm at a loss to explain why they don't all have black hair and gold eyes, but the rest of it makes quite a bit of sense.
 * Yamiko aren't created by the Keyblade cleanly splitting the darkness out of a person's heart. For this reason, they're "fake Unversed" - kind of like the relationship between Pureblood Heartless and Emblems, except reversed, with Yamiko being more naturally-occurring and therefore Pureblood Unversed, whereas Vanitas (and by extension, his creations) are artificial, thereby being the equivalent of "Emblems."