*blinks in remembrance to Metal Tim's post*
You know, you're right. I had forgotten about that. So it jolly might be the Sephiroth that Cloud chased all over the world!
About Aeris/Aerith... I'm sure it's Aeris. I have FF7 too, and that's the default name. Plus, the japanese language dosen't have a "th" sound. At all. Writing it in hirigana would spell it (in romanji) as: A-e-ri-su. I'm really not sure what it might mean, and I haven't seen it spelled in kanji yet. I have seen japanese packaging that has "Aerith" in english letters, but we all know how great the japanese are with english translations (see www . engrish . com). Also, there are scores of bootleggers in japan that put out "official" products.
In short, "Aeris" is the logical choice based on the semantics of the japanese language.