Good idea but you're not good enough to do it
First off, teasers suck.
Now that pic (i asume Terra) was ok for someone who's relitively new drawing, but trust me, you will never capture the essence of Yoshitake Amano's artwork. He's is far too high a bar to reach for us mere hobbies to ever come close to.
The fact is while this is a decent idea, I don't think you have the skill to pull it off, plus you're bound to piss off half the FF fanboys if you don't use the actual game diolog, hell you'll probably still piss them off because you won't protray it to thier own mental image.
Basicly put, leave an idea this massive to the pros, you'll only get buried by it.