2. Since none of these countries existed at the time, none of the people listed occupied these countries at the time. However all of them, including the Normans and the Burgundians occupied territory that was later to become part of (in a few cases, all of) those countries.
3. All the peoples listed (not merely the Burgundians) were "taken over" by later invaders or by the indigeous population.
4. By "static" Ishmael means, as I think he makes clear, unchanged i.e. the local population continued to speak the language they were speaking when the invaders arrived as opposed to it being "completely replaced" by the language spoken by te invaders.
Let me know whether you find the substantive theory acceptable or not.