Hi Christine! This is a fun evening to think about planning and I love that you are involving your children too!
My first thought since you are staying at the Wilderness Lodge is to plan an evening over at Fort Wilderness. You can either take the boat or rent a surrey bike. The bike depends on size of family. The boat leaves every 15-20 minutes from the Wilderness Lodge marina and is about an 8 minute ride. There is a bike path between Fort Wilderness and WL but bike rentals cannot be done after dark so this also depends on the time of year for your trip.
Fort Wilderness activities include carriage rides ($45-reservations
407-939-7529) and a visit to the Disney stables. They also offer pony rides for younger children if you arrive early enough. Dinner can be a take out pizza from Trails End and enjoyed at a picnic table or down on the beach. Wishes can be seen from there each night and the Electric Water Pageant goes by at 9:45pm each night. You might also enjoy Chip and Dales Campfire Singalong nearby where you can roast marshmallows and hotdogs and then enjoy the following movie outdoors.
Other locations that are super include the Boardwalk area where every evening there is street entertainment to enjoy. Also a large arcade at ESPN Club, Wyland Art Gallery, some shops, and pizza by the slice if you don't have dining reservations. Top that off with dessert at the ice cream parlor and then walk around the lake while taking in the beautiful sites and lights. You can add a boat ride to the Hollywood Studios and back for some relaxation and rest time too.
Last but not least you can head to Downtown Disney. Each evening there is street entertainment to enjoy and you can check out the movie schedule at the AMC theater where you can enjoy a Fork and Screen movie. This is where you will watch the show while they serve you food...very nice and comfy seating too. All choices will be fun for you as well as the family!