Personally I like the cute and animu style you've got going on here. I would like to point out - in the last picture in particular - that the necks are rather thin and... oddly curved. Personally I have always been of the belief that the neck doesn't need to be thinned to extremities to still maintain a 'cute' manga style, so you may want to address that if you feel like it. Since you asked for anatomy, I don't see much muscle development in the legs. Right now they are very linear, like tapered boxes. Look at real human legs and use that to influence your style. I would suggest you pay particular attention to the quadricep muscle group in the upper leg and the gastrocnemius in the lower leg.