Hi, there is a way to do both using My Ecobee device DTH (Custom DTH under the SmartThings classic mobile app).
With the default (stock) ST integration, you can expose the ecobee remote sensors, but you cannot use any other ST connected motion/temp sensors to adjust the ecobee tstat’s setpoints.
For the last 5 years, I have developed several smartapps to leverage all ST connected temp/motion/contact/presence sensors in order to implement similar features as the ecobee’s follow me and smart away features.
Refer to the following thread for more details on the ecobeeSetZoneWithSchedule and MonitorAndSetEcobeeTemp smartapps.
I’d personnally recommend the former as part of My Ecobee bundle at my store as it is based on the very powerful concepts of rooms/zones/schedules where you can create virtual zone devices to adjust your comfort (especially when used in conjunction with smart vents).
All the use cases and supported features are documented at the ST community wiki: