If you want to publish a fanfiction, write it as a blog post.
Do not make articles on this wiki for characters that you made up: this counts as fanfiction and must, therefore, also be published only as a blog post.
Information from fanfictions must not be treated as fact on character pages, especially not by the author himself. However, if a fan theory is very wide-spread, plausible, and tone-appropriate for Disney comics (e.g. Mr Duck being Daisy Duck's brother), it can be mentioned (though it's advisable for it to be appropriately referred to as a theory in the wording).
Fanfics must be appropriate and kid-friendly, no bad language, not too much violence, etc. Any inappropriateness will be punished with a block.