Also, the premodern Japanese lit tradition includes fanfiction as a valid form of commentary. I'm just saying. Accepted form of commentary, and it can either be great analysis, if the writer specializes as a scholar (Norinaga) or great art, if the writer is primarily a poet (Zeami). Or great neither, but still part of the tradition. I felt so validated when I learned that.

I wonder if that's why Japan seems so much more lenient on fanworks.

3 probably depends on how well you're connected to people and the community. I'm not at all, but for others, it'll be different.