This week the 4 teams will have two main jobs, Shape Language Analysis of their target artist/art style along with creating a first pass of proxy shapes for both the characters and environment pieces.
There are some very good examples of the shape language break downs in the Life Unfolds Style Guide.
The team should be building detailed analysis pages and clearly showing the shapes, lines and curves that are used to define the particular art style that they have chosen.
There is a nice section (toward the middle of the post) on this blog post https://floobynooby.blogspot.com/2013/12/the-cinematography-of-incredibles-part-2.html that covers the use of Shape Language in the Disney Pixar film The Incredibles.
The second part that the team will be exploring via shape language is the use of first pass proxy models. These models can be built in programs like Maya or ZBrush.
The fist pass of the proxy stage should be very rough models that explore nothing but rough shapes in combination with each other to form more complex objects such as characters or environment pieces. The proxy shapes should be an exploration of the rules that have been learned in the shape language analysis stage.
Scale and the relationship between you the viewer and the proxy objects are the most important thing at this stage, This stage of development will help you build confidence that what ever you build moving forward will have the correct feeling for your designs.