The only device that I would recommend for cryolipolysis treatment would be CoolSculpting. I would not trust any other device. It is possible that these other devices would not provide good results and also possible that they could harm you.
I would consider safe to use cryolipolysis over an area with a cyst or lipoma. As you may know, the cryolipolysis would not treat the cyst, but it should affect any fat in the area.
The only cryolipolysis treatment that I would perform on patients is CoolSculpting. This is the original and well-studied cryolipolysis treatment and I would say the safest.