Basch - strongest one-handed weapon (right now an axe), shield, mix of heavy/light armor depending. The least magic, but catching up now. Basically a fighter.

Vaan - I'm testing between a 2H katana that's slightly less attack and the same weapon/shield setup as Basch. So far, the katana hasn't hit multiple times enough to warrant it. Light armor. Has all the black/white magic available, plus basic other magic (protect, etc).

Ashe - bow, mystic armor. All the magic that I have so far available, including green/arcane.

I've been ignoring the technicks for the most part (besides the basics like Libra and Charge). Basch may venture into that territory soon to see if any are worthwhile. Augments/quickenings were a first priority, with armor and weapons when necessary.

Balthier, Fran, and Penelo are all neglected outside of learning whatever they need to in order to get quickenings.