Just a bit of information for you: in case you have some queries about the WTS, you can find our Wiki here
In case you're looking for a specific translator, please see the list of available translators on BabelZilla
When you select the desired one, you can send him/her a P.M. or an e-mail (if and when public).
You may also insert a new Topic in the Help
Section, in order to ask for specific translations, to write a general request about missing translations, etc.
* Please note that there is not much point in including an en locale, as that is not on the Mozilla list of supported locale codes. You may also want to consider dropping either ja-JP or ja, as those will probably the same too with no effect in user experience.