Hi there, Becky!
One of my very favorite fireworks shows at Walt Disney World is Illuminations: Reflections of Earth that takes place at Epcot each evening at 9:00 p.m. It's absolutely not to be missed!
The
Electrical Water Pageant is a fabulous "parade" of lighted floats that make their way around Seven Seas Lagoon and Bay Lake each evening. It's such a hidden gem and I think you should definitely try to see it while you're visiting if you can. I'm not sure you'll be able to make both things happen on the same night though. You can take the monorail directly from Epcot to the Transportation & Ticket Center. Illuminations is about 12 minutes long and then you'll need to walk out to the entrance of Epcot to catch the monorail. A lot of people leave the Park right after the show so you may have to wait for a monorail depending on the crowds.
Here is a list of the current times and locations for the Electrical Water Pageant:
Polynesian Resort -- 9 p.m.
Grand Floridian -- 9:15 p.m.
Wilderness Lodge -- 9:30 p.m.
Fort Wilderness -- 9:45 p.m.
Contemporary Resort -- 10:15 p.m.
Magic Kingdom turnstyles [when Park is open past 10:00 p.m.] -- 10:35 p.m.
I'm thinking you'd have a slight chance to catch the the showing at Disney's Contemporary Resort or at the entrance of Magic Kingdom Park, but you'd really be pushing it to make it on time. Once you arrive at the Transportation & Ticket Center, you'd need to switch to the Resort monorail to the Contemporary or Magic Kingdom Park. My best advise would be to catch it on a different evening if at all possible.
I hope this helps, Becky! Please let us know if you have any other questions we can help with!
Have a Pixie Dusted vacation!
~Jackie