I think these are pretty well done. I personally like a shallow depth of field even for headshots, and to me the eyes all look like they're in sharp focus as well as other important details, however the shot of the man could stand to be selectively sharpened in some areas. Based on my personal preference, I don't think there is enough separation between your models and the backgrounds in the shots of the blond girl and the guy; I think a little more room behind them as well as casting less light on the background would bring more focus to your subject while adding some dimension to the shots.