Right now they're doing a campfire and roasting marshmallows from 7-8PM. Great fun. My kids had a blast. Then a movie is shown on a big blow up projector screen on the beach. They pause the movie for the water pageant (a little after 9) and wishes (a little after 10).
One night during labor day weekend all the lapu lapu pineapples were gone by 9:30. I wasn't ordering one but I overheard the bartender. He offered to make the same drink in a plastic cup, but I can't imagine ordering that.
I'd head out to the beach after dinner. Just don't miss the last boat back to MK if you need to catch a bus. We learned the hard way they don't take new passengers back to MK after it closes a few years ago. Ask a boat captain what's the last boat you can catch, don't trust the concierge CM. We ended up on the monorail, however it has shorter hours right now.
The beach was never crowded, but you may need to head away from the movie to hear the wishes soundtrack.
We had dinner at Ohana at 7:10 and just made it out for the water pageant around 9:10, if that helps.