Really weird that RPG Maker XP has battle Sprites that make reference to their related Battlers (the data), but the Battlers themselves don't reference the Sprites.
This feels backwards to how things are normally handled.
Currently I'm changing the sprite graphics from the Sprite class, but since that doesn't update the battlers, referencing them to get the current sprite (as you would) doesn't work.
It's likely I'm approaching this the wrong direction - I altered code that checks if Sprite graphics have changed, not the part that defines the graphics itself, which is in the Battler class.
The former point still stands though.