In the U.S., aiding and abetting a violation of someone else's copyright is itself a violation. Of course, there are things a translator can do to assert his/her rights (because people who create translations also own the copyright to the translation). For example, Skyblade could counter sue for an injunction against Square publishing the game in the United States (because it violates the translation teams' copyright).
Let's assume for that Skyblade actually had the funds to actually assert that defense in court (which is sadly what a lot of copyright law comes down to).
DISCLAIMER: I AM NOT A LAWYER.
I'm skeptical as to whether or not Skyblade would be eligible for copyright in the first place. Translators seem to have a clear claim to copyright, barring some agreement to transfer or forfeit those rights. However, as far as I understand the predominant copyright regimes, the holder of an intellectual property has the exclusive right to authorize derivative works of said property. Although translations are held to have enough original elements to be eligible for copyright protection, they are also most certainly a derivative work.
Can someone claim copyright protections for their work when said work infringes copyright? This is not an easy question, and certainly not settled; however, precedent is not on the side of the first infringer. As such, since Skyblade and co's translation was A) unauthorized, and B) derivative of S-E's IP, it is not eligible for copyright protection by my estimation.
If I'm wrong, please direct me to the relevant law and/or case.
Now, let's say that infringing works
do merit protection for their original elements. If the rumors are true, Squenix already had a translation in the works for the PSP version (not to mention the upcoming release). Since those easily predate the existence of the fan project, the copyright over said translation(s) trumps the translation cooked up by the team. Remember, it's not which one was published or registered first (although those save you the trouble of having to establish when an unpublished thing was created), but which was created first, as copyright is an automatic thing.
tl;dr Fan translation is legally screwed on multiple counts.