Oops!

[Goldenboko]

Make sure to balance your teams well. That's all I can tell ya.

Is it possible to train (as in leave the place where he asks you if you ready)...

Because Locke and Terra could use alittle training

[Roto13]

I don't think so. I haven't really tried.

[Xurts]

You can divide your teams however you want, it all depends on your preferences. Just make sure to fight the Rider with Locke in your party because he can steal a Mythril Vest. When you fight Kefka you should definately use Celes. Kefka uses some pretty nasty spells, and having Celes Runic makes the fight much easier.

My three parties looked like this:
1 - Terra, Cyan, Locke
2 - Celes, Sabin, Edgar
3 - Gau

I never bother learning Rages, so Gau is useless to me. I had party 2 guarding Banon, and I used party 1 to go and destroy all of the Imperial forces. Gau just hid in a corner. Party 1 fought Rider (for the Mythril Vest) and party 2 fought Kefka.