I been working on my next revision of my Schema Plugin to work not only with your latest commit, but also resolve that issue where if I save the Schema Data it breaks the ajax for TablePress editor.
I decided the best approach would be add a tab and build a new UI from there.
I built a class extending the class TablePress_View and have it showing up as a tab and in the sidebar properly. But when I try to read $data its only giving me a array of the tabs and their settings that wads defined in init_view_actions() in controller-admin.php.
My plan for this revision is to have a list of all the tables and when you select one to ajax load a new Schema settings interface. And when they save to save it to the $options for that $id vs saving it to its own table in the WordPress database. So I need to figure out a way I can list all of the tables, access the data in them, and save to their options. By looking at the Auto Import plugin I can mimic what you have for saving the options. But since it extends the Import class I think the access to the $data is being handled by that class. Yet I can seem to figure out the correct public variable to access $data.
If you can point me in the right direction for this that would be great.