Not covered here: fonts and glyph appearances, which will nearly always end up displaying wrong in certain Asian languages -- https://heistak.github.io/your-code-displays-japanese-wrong/
Thank you for this. I tested it immediately on my site. Now, during testing I looked at the debug output before I browsed to a page, and the debug output was displaying the wrong characters, hanzi instead of kanji. But, when I browsed to the actual page, the characters were right, presumably because I'm setting the lang attribute in the HTML tag. Thank god I did that.
Still, testing this uncovered a bug in my Traditional Chinese code, so there's that to fix now :)