I like the overall idea you had here, but some problems here with dark shadows and bright highlights are hurting it. I think this sort of shot calls for some HDR or HDR-like techniques.
4 - Nice concept, but I think the lighting isn't enhancing your subject and with the dominant overexposed sky area, they are getting lost, perhaps waiting until the shadows changed place and the sunlight hit your subject - or otherwise with this as is, maybe a conversion to sepia or b&w may have given this a little extra.
Nice idea, but the sky has been over exposed quite badly. My eye wanders up from the girl into that white space. The eye always goes to the lightest part of a photo, use this to pull the viewers eye to where YOU want it to go. Compose the image so the lighter areas are around the main focal object.
that is one big tree.....personally I would rather see more of your subject, closer...in this shot she is so little....mind you, you have a good shot...I just would like to see more detail of her...