I don't find the backgrounds in #1 & #2 are helping the shots. Maybe not in #3 either. The symetry of the background is interesting (in #3) although the lights seems to be like the proverbial "tree growing out of her head".
In the first three shots, the proportion of model/background favours the background. This tells me you want us to think the background is an important part of the shot.
#4 has a nice feel to it, although the lights seem to be placed too high, giving a shadow on the eyes.
