You can import all renderable cameras, camera planes, lights, geometry and locators. When you import a scene, a new composition is created within a Reaction node with all 3D data.
The name of the created composition (the one that contains the Reaction node) is based on the name of the FBX file. However, 3D updates are not supported; you can only overwrite the existing composition. To update a composition, you can transfer objects from one Reaction node to another by copying and pasting.