@gebjeff,

First off we can never recommend using your device through a third party service as we cannot guarantee the device's safety and functionality at that point. This especially applies to third-party services that require your username and password associated with your TP-Link ID. While you may trust the connection, you are placing your login information in the hands of another service, which may not be stored as securely. 

I cannot see this working however, due to the fact that the cameras are not a part of the Wi-Fi network and communicate with the Hub - you would need to communicate through the Hub. Furthermore, RTSP is not supported on the cameras from a technical standpoint. Due to their battery and low-power nature, a constant RTSP connection would cause rapid battery drain. You would be better off looking at methods to automate the notification and events on the hub.