(This concerns FF2 for the NES!)
Recently I started a new game, where I had Firion act like this Paladin guy.
So, there I went on, leveling up his Cure spell forever (LV5 before entering Phin, yay me) and each time I finished a fight, it said "Soul Up" but he decreased in neither Power nor Vitality, not even once.
Couldn't you use that to your advantage?
I mean, if you're really ambitious you should be able to mega-boost his Soul until it reaches 99, then start with Power (or was it Vitality?) until THAT reaches 99, then work up your somewhat decreased Soul and so forth until both of 'em have been worked up to 99.
So, theoretically, shouldn't you be able to boost EVERYTHING to 99 with patience and proper planning?
I mean, it seems fully possible.