The Japanese Air Law is based mainly on the FAA Regulations, so if you have a decent knowledge of those then you'll be fine. Buried in this thread, somewhere, is a book recommended in recent years for the interview but you'll have to look for that yourself. When I did the interview process there were no technical/written questions, just some basic stuff in the interview about runway lights, CAT III and oxygen.
You will be given everything you need for the Japanese Air Law. There is no need to study it beforehand and you'd probably just do yourself a disservice, as they teach you what you need to know.
Your sim check will be in a 767, no matter what you currently fly.