The Food & Wine Festival doesn't generally have a lot of effect on the availability of regular restaurant reservations. In fact it might free some up, as festivalgoers forego making restaurant reservations to nosh around the World Showcase or book special events.
What is more likely to affect restaurant availability at this time is free dining.
Values get free counter service, deluxes and moderates get the basic plan. Any free plan can be upgraded to a higher level plan by paying the difference.