To bacon and Schina.
Fan translations may break the copyright law, licensed or not, because it's a derivative work of something. As a matter of principle, it breaks copyright law even if the work isn't licensed in the US (there are a few agreements regarding that, TRIPS, WIPO, Berne...). You could try to challenge it as a fair use (in the U.S., other countries, such as the EU, don't have fair use provisions), but you'd have to challenge it, I mean, you don't get it by default.
And now is when things get murky: which country's jurisdiction apply? Remember that the US got Richard O'Dwyer extradited even if he was a UK citizen, was in the UK and his servers were in the UK. So, do Japanese laws apply or any other country's laws? Usually the laws of the country where the infringer is apply, but again, someone has challenged that already and could be tried again.
Now, a fan translation. It's an unauthorized work. You have to ask for permission to do it and a company could perfectly sue you for translating their work without their permission. Now, regarding if it's eligible for copyright or not, it is, but with caveats.
Translation copyrights belong to the translator, but they are linked to the copyrights of the original work, they aren't independent. That means that, for example, if another one wants to use the translator's work, he has to ask permission to the translator and to the original author. Still, remember that some translators have waived their copyrights.
Now, we get into murky waters with fan unauthorized translations. They do have copyrights, it seems, but of course, feel free to bring that to a court. Yeah, sue the original author or a company that has the license in your country for your infringing translation. You may get paid something for your translation, but for sure you will get bled away when they sue you for your translation too. That's, of course, if the judge doesn't decide to get you for "commercial scale infringement" because your site had a few ads or accepted donations. And then is when you get into really hot waters.
Of course, no company worth it's salt will use a fan translation "as is". They will usually do their own translation, and if yours is good enough, well, they will change enough things so that yours and theirs can't be linked in any way.
Though, to be honest, I've seen plenty of professional work with the same or worse quality as fan translations. And the worst part is that it was English to Spanish, not Japanese to English. But well, that's another issue...