You might like 'Horimiya'. It shares similarities with Shikimori in terms of character dynamics and the light-hearted tone. Both show the growth and interactions of the main characters in a school setting.
The ending of the Shikimori manga is quite satisfying. The main characters reach a conclusion that feels right for their journey, and loose ends are neatly tied up.
One common theme is the development of their relationship. Since they have an interesting dynamic, many fanfics focus on how they grow closer. Another theme could be adventure, as they are often involved in various events in their respective worlds.
Most likely not. Abuse in any form is an unethical and often disturbing concept. In fanfiction, it can distort the original intention of the source material and create an uncomfortable reading experience for those who come across it.
I'm not entirely sure as 'abuse' in fanfiction is a concerning topic. It could potentially be a fan - created story that involves some form of mistreatment in the context of the 'boku no dake' (which might refer to a particular series or character). However, such content often goes against positive and healthy storytelling.
Well, that's hard to say. Kawaii is a subjective perception. It could be based on your expressions, style, or the way the artist portrays you in the comic.