Custom Gamerpics and avatars have finally arrived on Xbox One today. A new update allows you to set up your new avatar on console or pc (not Xbox app), and can be whatever your heart desires.
We can only imagine the types of images we are going to see, but we're going to have to wait for that. Other changes include chat bubbles for the mobile app and co-streaming on console. Through the Mixer app, you will now be able to invite up to three friends to stream at the same time in a split-screen format. The chat bubbles will pop up only in Android phones, and create a bubble in your notification bar. These will be on by default for both chat and clubs, so you'll have to turn them off if you don't want to be disturbed.
Individual controllers can be setup to specific gamertags now, and will be done through the settings menu. Make sure to be signed into the profile and using the controllers you want at the time.