These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Fanon: Although the identity of A-Ko's parents is just a Shout Out in the series, Fan Fic based on this series almost always sets it somewhere in The DCU.
Word Of God says A-ko's parents are those two, it's a convenient way to explain the super powers.
Les Yay: Sort of. In the original film, B-Ko seemed to have a rather ardent fixation on C-Ko, which was made clear in a scene in which B-Ko, bathing in a giant Roman bath, touches her breast as she thinks about C-Ko; while the lines in both the original Japanese and the dub are ambiguous in their meaning, the implication is clearly there, and is likely a holdover from its hentai origins (see Bleached Underpants above). B-Ko's...affection for C-Ko was toned down in the sequels, and practically non-existent in A-Ko the VS.
It does arise again in one of the direct sequels, as the main characters each interrupt class in turn with their Did I Just Say That Out Loud? excitement over their spring vacation plans: B-Ko's plans apparently involve "one night of passion with C-Ko".
Memetic Outfit: A-ko's Transfer Student Uniform; when Central Park Media was publishing comic adaptations of the series, they changed her outfit in their version of A-ko the VS to the sailor suit to increase sales.
Moe: Assuming you don't hate her guts, C-ko could invoke this.
Porting Disaster: The original DVD release of the Movie. The master had degenerated and it's nearly unwatchable (the Laser Disc and tape versions were fine). CPM eventually released a Special Edition (completely remastered, it's the yellow cover one), which is great, but hard to find and hideously expensive.
The Scrappy: C-ko has a healthy hatedom, with some (at least) fans believing that she's a Creator's Pet and/or Canon Sue. Kei does too, to a lesser extent.
Woolseyism: Somehow, C-ko is actually less annoying in the dub.