My home has a Bryant T6-WEM01 Thermostat. I had heard it was based on the Ecobee 3, so I tried to add it using my Bryant UserID and password. Guess what - It is now connected! I haven’t had a chance to try and program it yet, but it does show as a device, including motion detection and humidity.
Congrats, your lucky as my Bryant system has the evolution thermostat and apparently is proprietary and does not work with any third party thermostat. I understand why they did it but it still sucks as I’m locked into one of the 2 versions they offer.