That's a good point about the cameras if you are sure they didn't look at them. I know they did look at the cameras along Ocean Blvd when she left the Hotel and she was seen up until either 14th or 16th street south. That's either 4 or 6 blocks from where she left the hotel. That makes me think that none of the guys she had visited had anything to do with it. They would have had to have been seen exiting the hotel.
But as to your second point, she was of consenting age in New York and South Carolina so that wouldn't have been an issue.
I am talking about the weekend as a whole. Providing alcohol at his hotel amongst other things, helping her get into the club and providing plenty of alcohol there according to her friends. It also sounds like back in ROC he is not a stranger to girls around her age.