Zwave is proprietary. Zigbee is "not really" open. There is no open implementation AFAIK, the application library (cluster library) is standardized and everyone is allowed to develop and sell compatible devices, yet you won't be able to fetch the code and deploy on the platform of your choice, AFAIK. In this regard Zwave and Zigbee are quite similar.

Almost all the mentioned standards are based on IEEE 802.15.4.

The difference between 6LoWPAN and and the rest of the mentioned "standards": 6LoWPAN is IPv6 "adapted"/compatible. Thread is based/extends on 6LoWPAN, and adds several missing features or replaces some parts, because similar to conventional Internet devices, you need something more than IPv6 to get things going.