I actually love this character, but I have some different thoughts on the proportions.
I thinks it’s mainly her low waistline combined with narrow hips and legs that’s causing her to look top-heavy. Your reference is stylized, and that’s not a bad thing, but if you look at the grid on the first, yours has a lower waistline (though I admit I don’t particularly like fashion croquis stylized anatomy, and am glad you gave her better thighs so she doesn’t look like she’s starved). On the second, yours has a narrower and slightly lower waist, and narrower hips and thighs.
Here’s what she looks like if we raise her waist, and if we raise and widen it:
That said, with the current anatomy, I’d still play the game and think she looks epic. She looks so awesome in your main presentation render the proportions don’t even register.