Many people on our cruise caught the fireworks that night, so you should be fine.
We hit all 4 parks that day and I didn't feel it at the time but wow were we exhausted at the end of the cruise. We woke up that day at 5:30 to get ready and be on a 7:30 bus. We made the 8:45 PM bus from DHS after we watched Fantasmic going back to the ship. Cabanas was a buffet when we got back, so by the time we dropped off backpacks and washed up, went back down for dinner, and did a little unwinding we didn't get robbed until after after 12:00. The next day (Thursday) was Marvel Day so that didn't end until about 11:30 PM. Friday I was just dead dog tired and after lunch went back to the cabin and slept all afternoon, I didn't get up until right before dinner. I've never been like that before on a cruise.