Hi Jolene,
My three boys absolutely love Teppan Edo at Epcot's Japan pavilion. They are mesmerized by the talents of the Chef performing at the table side grill and I think they would lick their plates clean if I let them.
I assume the dining plan that you are referring to is the Magic Your Way Basic Dining which provides one table, one counter and one snack per day. There are other dining plans and information on the plans can be found
here. For one table service credit each guest on the plan would receive one entree, one dessert and a non-alcoholic beverage. The adult menu at Teppan Edo provides a selection of beef, chicken and seafood including shrimp and scallops. The entree is prepared at your table and your selection is mixed with zucchini, mushrooms and onions and served with steamed rice. If you are allergic to any of the items used please be sure to speak to your waiter as your meal will be prepared separately.
I think a good rule of thumb is to allow 75-90 minutes for table service meals. I think it would be very tight to make it through the meal and outside in time to view Illuminations in its entirety but you may be able to catch a portion of the show. Another option would be to arrive a little early and see if you can be seated prior to your actual reservation.
On a side note, I highly recommend the scallops. They are incredible! Have a great time!