For the singing one, I think it was SACRIFICE, it's easier if you use a microphone to sing along. Otherwise with your mouse you just rapidly click while your supposed to "sing." If it's green you're doing it right.
As for some other questions, pretty sure that Rockit will be open as it was last year. However it can only be open until 10 if I remember correctly. It's lame, but people complain about the noise from screaming riders. Also about Stay and Scream, tried it a couple years ago and while some think it's nice to get some houses in early, I completely regretted it. It seems that it takes a while to get the houses fully staffed so the first few houses I went through were missing a lot. Just be aware of it and I don't recommend getting your favorite house out of the way first. The lines at Harry Potter should be less insane so I wouldn't hurry over to HHN. IOA is open until 7-8pm and HHN starts at 6:30. Save some cash by getting Stay and Scream unless you're a Florida Resident, then it's the same price. If you can afford it, get express for the busy nights and get them early because they sell out quickly.
Strange how little information there is this year. The other years we knew so much way earlier. Here we are less than a week away with only names and descriptions of houses and scarezones. No locations yet? Also noticed a description mentioning Cindy. Seems we will finally meet her.