How about this? I dont have a ref so I imagined the wrap would go over the shoulder instead of disappearing near the neck.

Cute and efficient base by the way

This is much better, but I think your mockup would benefit a lot from a more unified, connected palette. I like your shapes, rendering and the scale of objects, but the way you varied the colors from one piece to another makes me feel like you haven't tried to use the colors to give a specific mood to your game, which would be interesting if you want to improve it. However, I like the fact that you made closer objects more saturated, I just think that the shadows are varying their hues in too many different directions without reason. Was reserving outlines only to active/moving sprites a councious decision? You have many different outlining rules in the same piece, I didn't  liked it so much, but that is just personal preference, it is a perfectly valid way to do it.

They look fine to me, the sharp highlight lines give a plastic vibe but I think that is intended for the barbie look, perhaps the outline could use the second darkest share instead of the darkest one, but this is it, I sincerely don't have much to add to the hairs, nice work. The reddish darkest skin color showing through the hair's alpha is  clashing with the hair color, I would go for a more purplish desaturated shade with enough contrast with the dark hair. Also the jaw lines read a bit like banding, but think that is not the focus here.

Gotta love these big tiles, noiseless, nice details, not overdone  Grass is a little flat and too green?. It gives a western vibe, and i take it that by desert you mean rustic dry lands, which is not what we imagine when we read the title "desert tile set". I agree it is way too dark, it looks as if you wanted to depict it at a late sunset. This quick recolor might be quite far from what you planned but it shows how it can be a lot more readable with much brighter colors, but if you go brighter you might want to lower the contrast on the floor texture, giving its shade a different index from the sides of the cliffs.  Also, if you and to imply desert vegetation then you would probably want warmer/army greens.