>>121242090My personal definition of "official" is if the character in question comes from syndicated media. Anime, video games, cartoons, newspaper comics, that sort of thing.
There's a gray area when you get into self-published media, like webcomics and YouTube/Newgrounds animations. Even Fol'Amor falls into this category since it was a grad project.
In my humble opinion, Twitter/deviantART OCs shouldn't be considered "official". Posting someone like theycallhimcake's Cassie that's meant to be fapbait and nothing more is basically cheating, and they're not really iconic outside of porn communities anyways.
I find there's a certain intrigue to characters that "fly under the radar" or are "borderline" like Jessica Rabbit or even Sunny Miami. It gets even better the more obscure they are, even though that usually means the character gets much less fanart, which is suffering.