#3 is your strongest image and most natural.

The background looks as if it was added in post. especially #1 and # 5

The light is coming from the left and right, but there are no shadows at all. In addition the angle at which the image was shot, would represent the stream angle of the background.

#4 is a good shot as well, good expression, nice light on the hair to add depth on the curls, nice catchlights in the eyes and lips. However i wouldnt have left as much headroom in favor for not chopping off part of her dress in the lower right hand corner.

same with #3, i wouldnt personally leave that much headroom and gotten more of her arm, that way it streams lines the image.