Japanese teachers, especially JHS teachers work crazy hours. OECD survey: Japan's teachers work more hours but teach fewer:The Asahi Shimbun. That said, I'm not sure if that translates into problems getting in touch or discussing things. You might just have to take a number and wait your turn. I quite often see parents stopping and being ushered into the small meeting room for whatever while I'm at work. (I'm a JHS ALT.) Every year, there is a 3 day period (I think it's about 3 days) when each homeroom teacher visits the homes and talks to the parents or guardians of each and every student in their class. That can mean visiting 40+ homes and having to drink a lot of tea. Every term there will be a morning of observation lessons when the parents can stand in the back of the class and watch the lessons. There are parent-teacher meetings and parent-student-teacher meetings, in short lots of opportunities to see what is going on at school and talk to people.
The very little parent-teacher communication you've heard about might be attributed to the....how to describe it.....formal distance between teachers and the rest of society? I mean, they even call me "sensei", and all I do for a living is trick children into communicating in a foreign language by playing games with them. Japanese teachers and the schools, for whatever reason, have a greater role, a more explicit and formal role, in moulding children into productive, ethical and moral members of society than schools do in the States. There is a cultural understanding (for better or worse) that school is school and the parents are turning their children over to the schools to temper and polish and make fit for society. Once the kids put their uniforms on, they become students and become the schools' responsibility.
You have to remember that all "communication", not just "parent/teacher" over here will come in a different flavor than you might be used to. Things are a bit more formal, appearances are more important, things are done in the background and slowly so as to not cause a fuss.
In short, if you call the school, someone will do something to try and help you. How timely or useful help will be will depend on the school. But speaking from my experience, they will try. Like the bullying, not something I'd be overly worried about. But like everything from grocery shopping to dealing with city hall, language and cultural barriers will make it more difficult
Allow me to add:
from my experience
There can very little teach student communication outside the classroom because teachers also coach clubs, and if they are doing an active club (e.g. basketball, baseball, brass band) it is a daily thing, and so a student that want extra-help cannot easily track down their teacher- instead they need to schedule an appointment and the teacher will not go to practice (usually 2 teachers) and meet with the student. As you can imagine, not many students meet with teachers...
from my experience
as far as parent-teacher meeting, I think it is twice a year, plus one home visit. After the first year, try to stay at the door and just peer in.
from my experience
Meeting teachers or even the principal is very easy, even without an appointment. But most parents "leave things up to the teacher" (as far as I have seen).
Joining the PTA, or other similar school groups also provides "easier" access, as does being involved in the school, school events and so on.
I know there seems to be a lot to worry about, but if your daughter is positive about going to Japan, that her initial enthusiasm will help her over the humps (I think it would be much harder than if you were starting from, "You are ruining my life by moving to Japan.")
hope that helps