@DarkChaplain, while it references Leá Monde it's highly unlikely to even reference Vagrant Story. Mainly because of the Final Fantasy motif. This which strongly suggests it will reference Final Fantasy XII more and can therefore be considered a possible sequel and not an original Ivalice story.
This lone mercenary could be Vaan for all we know. Yea Vaan wasn't much in the flagship title, then gained a bit more depth in the DS sequel, but this could be his actual defining moment. One that they wanted us to see in the full-fledged Final Fantasy XII. Vaan as an accomplished Sky-Pirate, more so then his Tactics A2 counterpart even. Still it's all nothing but speculation.