LogFAQs > #950558976

Tomb of Raithwall.

Anyway, if you want to do everything the game has to offer, or even most of it, I advise not ignoring any of your party members when it comes to leveling them up. You usually don't get a Game Over until all six of your main party members fall, so you technically have access to two parties of characters. As for the characters....

Vaan and Ashe are technically the best party members in the game statistically when it comes to physical attacker / jack of all trades and magickal attacker / jack of all trades respectively. Seriously, they can both fill any role well at the very least.

Balthier is primarily good as a physical attacker / support mage and that's pretty much it. He is basically a worse Vaan stat and role flexibility wise.

Basch mainly suited to be a physical attacker, as he is the best for the role with the highest Strength for the large majority of the game and post game, and probably the best tank due to probably having the highest Max HP, but only by a slim margin compared to Vaan. Unfortunately he has the worst Max MP, lowest Magick Power and Vitality(Vitality just determines resistance to status ailments, reduces the amount of time some are active, and also increases the amount of time stat buffs are active as well. It also influences damage with a small few weapons. Thankfully it has nothing to do with Defense and damage resistance / reduction.), although having the lowest MP may make it a bit easier fill up his Mist Charges.(Untested by myself. Just a theory.) So If you do make Basch a secondary support mage make sure he sticks to supportive magick and that he also isn't the primary support magick user either. He's like Balthier but even more physical oriented and a better tank, but with worse potential as a mage as he isn't quite as strong and is less flexible in that aspect.

Penelo has the highest Max MP and pretty good Magick Power thus is probably best suited as a mage, either white or black mage for stronger heals or more damage.

Fran is the tankiest female character by a pretty slim margin considering she'll probably have the highest Max HP among them, but she is also the cast "true" jack of all trades due to excelling at nothing stat wise, save Vitality, which she has the highest amount of any of the main characters. The rest of her stats are either a bit on the higher end, or all middling. So feel free to assign her to do almost anything. I recommend using her as a physical attacker / healing / support mage hybrid.

Anyway, yes IMO, a white mage becomes fairly important to have around this point going forward if you try to tackle hunts ASAP and aren't abusing Trial Mode items, etc.. If the party you listed is who you mainly want to run with definitely consider making Ashe your white mage.