1. Looks a little underexposed to me, maybe crop it in a little tighter on the left and get rid of the marks on her arm. Should be able to fix that and turn a good shot into a great one.
2. Lens flare isn't usually your friend. Depending on taste a little might work well in this shot, but not that much. Try brightening it up a bit and see if you can get rid of some of that lens flare.
3. Looks great on my monitor. Great shot! Get rid of that blemish of some kind on her face and it'll be PERFECT.
4. Little too much in this shot for my taste. Maybe crop it in a little if you want. Colors look good except her shirt is a little too bright, if you can't fix that without lightening everything else I wouldn't touch it.
5. Great shot. I don't see anything wrong with it.
If your clients love them then that's all that matters. If you take any of our suggestions see if the clients like them or the originals more. Overall good job! I especially like #3. A little touch up and this is well worth framing.