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

[BG-57]

It is funny though. They all do have the exact same professions. Cloud is an ex-SOLDIER, Tifa is a bar owner, Vincent is a former Turk, and Yuffie is a materia-thieving ninja. I think they would more properly list it under a forced participation by warriors of far-off-world origin. Or maybe they're all actors portraying a role. After all, none of their attacks actually match up against the VII style. Cloud's Omni-Slash could be V2 or something . . .

I'm making excuses and then trying to shut them down. XiXiXi.

Again FFT provides the mechanics for your first suggestion: the transport device that carries Cloud over from the Planet to Ivalice. The actor angle is interesting, but I'm not sure what could be made of it.

The "Planet" in FFVII is named Gaia in some Advent Children publicity material from SE.

We had the same debate at Wikipedia

There's no reason why it can't have more than one name, although 'the Planet' is the established term.