First off the EWP should come past the Grand Floridian around 9:15pm.
Your comment about no fireworks struck me as odd. There are fireworks that night, in fact they be the best fireworks at WDW. There is a Pirate and Princess party that night and it includes an incredible fireworks display. There is also a soundtrack with storytelling during the party so Narcoossee's may pipe in the sound.
I suggest calling the Disney info line to get details of the party, planned time for the fireworks and find out if you'll be able to see them from the Narcoossee's deck.