There is as much disinformation out there about the JK Rowling contract as the Marvel contract. I will say this:
- Nothing in the contract specifically forbids HHN (although any changes to the area would require her approval, but that goes for anything).
- There was a rumor years ago she was the VIP who hated all the booze at HHN, which resulted in the removal of shot girls for the rest of the event. I've since heard it might not have been her after all. Even if it was, easy to keep shot girls out of DA.
- The only official word I've seen from Universal Creative was a tweet saying "we don't know" if we can use the area.
I spend a fair amount of time on the HHN boards, and I've yet to see a definitive answer on this one way or the other.