Cool sculpting should be safe after the lapband procedure as long as enough time has passed since the surgery and your physician has cleared you for the surgery. Please be certain to consult an experienced board certified physician for this procedure.
There is no reason that you can't do Coolsculpting on the abdomen after a lapband or gastric bypass surgery. If the problem you are trying to address is more lax skin than fat it may not be ideal however. It would be best to consult a board certified plastic surgeon that is also experienced in Coolsculpting to evaluate if you are a good candidate for Coolsculpting or would be better served by a tummy tuck procedure. Good luck!