This type of question is not proper. It's important to respect people's dignity and avoid engaging in discussions that might be demeaning or inappropriate. Katrina Jade's image should be treated with fairness and respect.
Again, without knowing the exact Lilly Manning story, it's hard to say its significance. But generally, a story can be significant if it teaches a moral lesson, like kindness or perseverance.
Well, in many 'Astrid and Lilly Save the World' fanfics, they often expand on the unique friendship between Astrid and Lilly. Some fanfics might focus on their adventures that were only hinted at in the show. They can be really creative in coming up with new monsters or challenges for the duo to face.
I'm not sure specifically which 'Lilly Collins ghost story' you mean. There could be many fictional or personal accounts related to her and a ghost story. It might be a story she told in an interview, or a fictional piece she was involved in.
Definitely not. Such fanfiction that contains sexual elements is not suitable for general consumption. It can also be disrespectful to the original work and its intended audience, which is usually more interested in positive and proper character development and storylines.