Would it be possible to control and Ecobee smart thermostat with this remote?
Not yet but looks interesting to integrate on Haptique. We can certainly allow Homey or Home Assistant to control it.
In this context, the question: What about tado thermostats?
Thermostats are not our priority to be honest so we have not added them. But we can add the support in next update. We will need to buy these units for testing. So possible but not coming very soon.