@Christopher, z-wave or zigbee sensors would not communicate with ecobee3 directly (as ecobee3 can only talk to its remote sensors with the same proprietary protocol)…
However, as mentioned above, the ScheduleTstatZones smartapp above could communicate with all sensors (whether ecobee’s remote sensors or z-wave sensors) thru the ST platform and calculates the avg temp from all of them.
Using the CT-100, you’d still miss some features from the ecobee3 as discussed here (see my post about pros & cons of z-wave thermostats vs. ecobee3):
But, at least, you’d be able to leverage your CT-100 thermostat as much as possible (till you switch to ecobee3 or any other “smart” thermostats out there).
Regards.