The default setup is meant to be a starting point. Additional features, such as the i18n module, can be incorporated into the classrooms by following the standard setup procedures.
The classrooms are built upon a combination of Nodes, Panels, Views, Taxonomy, and Flags. Additional contributed modules that add features to these modules should play nice with the online classroom module.
Additional fields, like a node reference field, can be added to the classroom content type to give you an easy way to show other content from your site.