Well, I don't remember much but here goes:
Marine can always use Red/White orb to boost attack/defense but there isn't much to do after that.
Karine should use Martial Mind before the fight, Fighting Spirit during the fight. I don't know if the snail can be scared but wouldn't hurt to try.
Salome as a mermaid can heal all your party members at once.
Well for a good party tho I'd recommend Marine Karine Benoit and, well, Dee has great spells but she's too weak. Merline might work if you explored the Ancient Temple and have a good weapon for her. And Salome is the 3rd option. It is long but doable
