Will CoolSculpting work on this hump? (Photo)

I wouldn't recommend it, we all tend to think that fat cells have the same shape and compsitition in our whole body, but the fat thats on the lower back has a differente composition (the cells are larger in size, because they have a complimentary function which is to store heat and keep us to our core body temperature). Althoug PAH is not frecuent, treating this area with coolsculpting could increase the risk. I would recommend kybella, if you're not a fan of needles, maybe INDIBA or any other radiofrecuency or surgery

We perform lots of liposuction and we used to do a lot of CoolSculpting. We still perform CoolSculpting but not as much anymore. We are very selective now about who we do Coolsculpting on. We find that CoolSculpting is great for people who want to spot reduce a little bit of fat so they can look better in their clothes. Abdomen and flanks with fluffy fat seems to respond the best.
Here is why I don't think CoolSculpting is the best option for you. The fat in the lower back tends to be denser and there is more risk of developing PAH (Paradoxical Adipose Hyperplasia) in this area. This is where the fat actually gets bigger after treatment. If you develop PAH, it is not easy to get rid of. You will need multiple sessions of a specialized liposuction using Vaser and Power assisted techniques to break up the fibrous fat that develops. Even if you do not get the PAH, Coolsculpting makes liposuction in the future more difficult. Since you mentioned liposuction as a possibility, I would recommend that you wait until you are ready for liposuction and do it then. A skilled surgeon will be able to sculpt the area and give you definition of the buttocks which can look really nice. You can't do that with CoolSculpting.

I have not used CoolSculpting to treat the area of concern to you above your buttocks, but I think it is possible that it could help. I think there is fairly low risk, so if that issue bothers you, I think it would be worthwhile to try CoolSculpting there.