Hi,
maybe you already have such a lesson but just in case, I would find it very interesting to have a few lessons on having lunch or nomikai with colleagues. Would be a great way to show how the various formality levels work between colleagues, twoards a boss, from the boss to the staff and finally, how it all gets mixed up once everybody is sufficiently drunk (which at least where I worked happened after the first beer... which did not stop them... unfortunately).
So how about it?