FAA, ICAO all the same.
As for Radio License, from what I heard you have to go through a course but no exams.
For reference, my previous company have a syllabus for ICAO A320 rated pilot.
70 hours GS (non rated is 180 hours GS). This basically covers air law, ops manual, Emergency stuff and so on...
14 hours or 7 lessons of FFS + JCAB practical ck (non rated 28 hours or 14 lessons)
2 days of Line ops GS.
8 sectors OBS (usually done in two to three days)
4 sectors of PM and 50 hours of line training (mostly domestic routes) + JCAB Line ck (non rated is 100 hours). Two to four sectors per day.
Compare to 'Big Boys' like AJX and NCA, LCCs provide less training to save time (and costs), especially for experienced pilots. We had a big negotiation with JCAB regarding issue but they finally said yes to it. Some pilots argued that they don't have enough time to study because the schedule were packed so I think the training department leaned a little.
Info might be little old, but I don't think there are no big changes...
I know leaving your country and moving to Japan is a big challenge. Hope this little info gives you heads up what to expect.
Cheers and stay healthy