An attack hack is something that changes a characters moveset. Those hacks are named FitName.pac and you can only use one at a time unless someone can make it the right way.
A vertex hack is like a texture, it changes how the character looks and is named FitName00.pac/pcs or which ever number you want.
FitCharMotionEtc.pac = moveset (motions), textures, and AI
FitChar.pac = textures, logic, and physx
FitChar0#.pac/pcs = models, textures, etc... (excluding audio)