One tip I do have is that before Odin becomes Raiden(if I remember correctly) use Odin to boost speed of lower characters because it is the only Esper that does boost speed.

Otherwise, I got everyone to learn every spell eventually, well at least my first time through. Oh, and I personally choose the sword over the Esper, if you don't know what I mean, you will. That's because the Paladin shield teaches ultima anyways.

THE JACKEL