I tried my hand at Triss, doing to usual shameless cheating just so I could get the proportions as close as I could, only trying to translate it to pixel art using your colors... Or to be more specific, I reduced the image and pixelated over yours while looking at the now smaller reference.

What I got from that was that the shape of her head (including the hair) is pretty round kinda like you did, but it tapers off a bit at the top.
You can see that if you try to fit a circle inside of the head, like:

Kind of like an apple seen from the front, but turned upside down, maybe?
Also notice how much her head is tilting:

(edit: threw in a couple plumb lines.)
And the jawline isn't as pointy. Adding more to the sides would make it look more like her, I think.
I worked a little more on Dandelion too. Now I think that the previous smirk was a tad too strong, so I tried making it a little more subdued with a shorter 'stache.

Maybe throw in some of that light purple for good measure?
