The Avatar SDK Unity Cloud plugin contains a full-body sample. Please note that it's just an example of how this can be done in the real app, and the low-resolution character provided is just a placeholder, you should replace it with your body models. This method works for any humanoid rig, but of course, you will have the seam between the neck and the rest of the body, which should be covered with some kind of collar.
If you need more advanced functionality (like the seamless attachment of avatars to your body models with texture blending), please contact them at support@avatarsdk.com.