I have never been to the BBQ, but from what I have found it is from 6:30-8:30pm. The Electric Water Pagaent goes by FW at 9:45pm so you would have plenty of time to do both. You could plan a carraige ride in between if you wanted to, since you would have time. They can be reserved in advance, you could book a 9pm ride which would bring you back around 9:30 and then head over to the beach for EWP. Just a thought since you would have extra time.