Why don't you use the spellcasing items on those fights?
1. Both Water Axes and the Mage staff are found in the Sea Shrine, and thus the probability of not having them is fairly high.
2. 3 shots of Fire2 won't necessarilly kill a ghost, and I'd rather kill one every hit then wait until the second battle to grease them all.
But that's one situation.
What happens when you have to face Kary and Kraken in the ToF? Unless you get super lucky and they use spells, you're down at least 1 or 2 black belts by the time you reach chaos.
You have to level too high, in my opinion, for a party of 4.