Hi, Kathleen!
You can actually arrive and check in at the restaurant as early as you'd like before your
Advanced Dining Reservation. You may not be able to be seated early, but you can definitely arrive early. I'm sure if you let the host or hostess know at the podium that you'd love to be seated early, they'll let you know if it's a possibility.
As far as arrival time for Fantasmic! at Disney's Hollywood Studios, seating begins 90-minutes prior to each show and I suggest you arrive that early to ensure that you get a seat, especially during the busiest times of the year. IllumiNations: Reflections of Earth typically begins at 9:00 p.m. nightly and as long as you are out in the World Showcase part of Epcot, you will be able to see and hear the show.
While there is not currently a list of Disney Characters and the
Table Service restaurants they appear at, there is an online
list of Character Dining restaurants where you can click on each one and see which Characters appear there. I'm hoping this helps!
Thanks so much for stopping by the Disney Parks Moms Panel with your questions, Kathleen. Please don't hesitate to write back in if we can help with any other questions you have.
Wishing you and your family a Pixie Dusted vacation!
~Jackie