I suggest that you completely remove EVERYTHING related to Ecobee. You may find it difficult to remove the “My ecobee” device, since (apparently) its parent has been deleted. I would also suggest removing ALL ecobee-related SmartApps and DTHs from your IDE - everything EXCEPT the files in the “sandood” namespace.
Then start over from scratch, running My Ecobee Manager to connect to the Ecobee Cloud, and then to add the one ecobee thermostat.
In the end, you should haveonly the Ecobee Suite Thermostat device, which will have a name like “EcoTherm: My ecobee” (you can change its SmartThings name through the config page)
Then yes, you should select this “EcoTherm:” device for Alexa and WebCoRE integration.