I would have the hip surgery performed first, and let that surgeon guide you on when he or she feels that you are ready to have the coolsculpting.
To my knowledge, there are no specific studies on this topic. Having said that, fat freezing has real effects on the fatty tissue under the skin. Therefore, given that it's an elective procedure and not an emergency, it would be a good idea not to freeze fat in the location that another operation needs to be done. Since cryolipolysis (fat freezing) takes about 3 months to complete, it's makes sense not to have it for the 3 months BEFORE your surgery. Also, since most surgical areas take 3 months to heal completely, it's a good idea not to have fat freezing within the 3 months AFTER surgery.
I have had many patients who have had Coolsculpting and then have had other procedures done. There is no down time and only perhaps some minimal bruising or soreness from the procedure. I would consult with your orthopedic surgeon as to how many months after your surgery you can have Coolsculpting performed. Coolsculpting is a great non-invasive procedure with excellent results.