i'd like to change some of the weapon power attack animations to be faster, and more effective, but i don't want all the enemies to gain this same advantage as the player.

i noticed there's a folder in in meshes animation data titled "female" and animation files placed in there only effect female characters.

could i simply create a new file titled "player" and put the new animation replacers inside?

You should unpack the Skyrim-animations.bsa and take a look at what the animations are called in there, then you can place the edited versions in as loose files, which overwrites the bsa.