Hi, Katy! My very best advice this close to your visit is to go to this website
Walt Disney World Dining Reservations and see what's available. There are some locations that book pretty far in advance, so check and see what is available for your specific dates.
There are a few dinner show options. If you want to see Wishes, I love doing the Spirit of Aloha luau at the Polynesian Resort. There are two shows nightly, but if you go to the 5:15 PM show, which is about two hours long, you'll be out in time to head to the beach at the Polynesian resort. From the beach, you'll have a wonderful view of the fireworks from the Magic Kingdom, and you can also watch the Electrical Water Pageant. It's a great way to spend an evening, and you can even pop into the resort for a Dole Whip while you wait!
Another dinner show option is the Hoop Dee Doo Musical Revue. This is a music and laughter filled vaudeville type show with some audience participation. Like the luau, this is a family style meal. There is a 5:00 show that will give you enough time to actually pick any location you'd like to get to in order to see the fireworks. You should even have enough time to make it back over to the Polynesian if you want to see the fireworks from the beach.
Have a wonderful time on your upcoming visit! I hope this helps with your planning!