...those little head... ring... antenna... bits look weird as hell. Like they look almost low-quality compared to the rest of the design and details.

I'd say this looks perfect, just ditch those.
Maybe replace them with some sort of headband-type tassels coming off the back, as opposed to the usual "pigtail" ones Nezha normally has. Maybe some kind of ragged cloth?
Nezha just seems like he should have something waving in the breeze with how much he's running and sliding around.