What World? There's no Timeline, shut up.

[BG-57]

What about I-VI & IX. In nine, a second planet is mentioned, from which Garland is transporting information on his entire world, meant to be programmed into the manufactured creatures, of which Kuja and Zidane originate.

Theoretically the world of FFIX and the 'other world' could be two of those three I mentioned that have been remodeled, like what happened in FFVI (although there's no evidence to support that line of reasoning). Same deal with FFI-FFIV; they haven't been tied to each other in any canonical way.

We're also forgetting another major player. Cloud, Tifa, Vincent, Yuffie, Sephiroth, and Zack (as well as a guardian creature very similar to Red XIII) all take part in the Ehrgeiz tournament. What do you make of that?

I'd file that under the same category as the parallel Aeris in FFT (same name, same profession, same appearance but not the FFVII Aeris).

cameo's = $$$$$

That too.