Microsoft Teams Avatar
Already a few weeks back i was able to configure my Avatar for Microsoft Teams.
Go to "Apps" in your Teams Client and search for "Avatar"
Add the App
Now you will be guided to create your first Avatar
Select one of the Avatars
You can customize the Avatar
Today when i joined a Meeting, i was able to select my Avatar. But for that you need to be in the Public Preview of Microsoft Teams Client.
From the Menu you can select "Effects and Avatars"
Now you add some Reactions to your Avatar