Regarding the 500h PIC time, I don't think you understand, how PIC is logged and Japan's regulations might hold a few more surprises for you.
You also need at least 500 hours (commercial) PIC in helicopters,
This means that you need 500h of PIC time AFTER you got your commercial license.
And there is another stumbling block. Apart from the US, I know of no other country, where you can log PIC time while receiving instruction. PACO can probably enlighten us with the Canadian rules, but that will not help you at all, if Japan counts them differently. On AOPA Japan's site (I think) there is the hint, that anyone applying for a Japanese pilot license must go trough their logbook and recalculate their flight time according to the rules of Japan.
If TC does not allow logging PIC while receiving instruction, you might end up well below that 500h threshold you are aiming for, even by Canadian rules.
Again, whatever the Canadian rules are, that can differ largely from other countries and will not help you at all. Canadian rules do not apply to Japan.