You've taken on a challenge. IMO, personal products are the single most challenging aspect of commercial photography with possibly, the exceptio of food photography, BUT it can be done.
As Trever said, #1 comes closest, but the exposure isn't quite right. You've got blown highlights on her crown and some on the hair thing (Not being desparaging, I just don't know what to call it...) as well. In #2, you've got an underexposed face and blown 'thing #3 is just weird; a single, OOF eye is almost never a good composiiton. #4 has possibilities, but you're not quite there.
First and foremost, you have to get your exposure nailed. This would be easiest done indoors (studio setting) but might not be the most appropriate for the product (Is there a particular event that you would wear these to, or are they "everyday"?) This means a perfectly exposed product and model. Next, your setting; backgrounds are critical and the ones in #s 1 & 2 are, to be blunt, awful. Next details... comb her hair, make sure she stands up straight, no forced expressions and probably most critical, coordinate clothing with product.
I think if I were to take a stab at these I would take a two prong approach. One would be close-ups of the products on a dummy head to really show-case the detail, and then other side would be to show the child/ren wearing them, which I would do in a high-key studio setting in a rather minimalist manner; that is: the child sitting on the white seamless holding a beachball or some other toy (that didn't detract from the product. Dress the child in complimentary, but muted clothing and use complimentary, but muted props.
This sounds like it could be a really cool exercise. Good luck!