I think the main problem you're stumbling into is that, when you anthropomorphize the sprite, you're not exactly following how human hair 'works' so when you apply it it doesn't look right. It's clear that you want short hair, but even people with short hair have hair all the way around the back to the base of their skull
, and while your portrait image would indicate this is true, a few of the other angles do not reflect this at all, giving the hair a wig-like appearance. To correct this, I made an edit that tries to approach the style and spirit of the portrait while adhering to 'humanistic' traits such as providing for a forehead and having the hair curve around to the base of the skull, like so:
1. Redesigned the hair to look spiky like the reference image.
2. Made the hair curve around to the base of the skull (neckline) in each frame.
3. Cleared the hair upwards to reveal the forehead and give the eyes some distance and clarity from the hairline.
4. Corrected posture issues in frames 3 and 4 where the legs were just too misaligned to maintain balance.
The posture issues I corrected are mainly because his leg was simply too far back on his body in frame 4 for him to have any hope of balance. In frame 6, the positioning of the right leg just didn't match the angle of his torso. Moving his left leg back a pixel or two (or making it larger) would further help with giving him a better sense of balance.
Hopefully this helps.