I think both nights are going to be very packed.. Since they are back to back I can't see people coming for 1 and not the other. I think the second night of happily ever after is going to be the worst. It's been school competitions at espn on the weekends and the last couple saturdays have been insane with just them. Add in the new show on top of it and everyone who decided to see it the second night instead and it's going to be a full house..
Also lets not forget that the AP previews for Pandora also start this saturday so that's going to bring in more people to the area who are going to add the firework shows to their list.
Disney has already announced that backstage will be opened for more room for people to see it in front of the castle so they are expecting thurs, friday and saturday to be well above normal crowds. They only open backstage on july 3, 4, xmas, nye and nye eve. It's going to be NYE sized crowds I think.