I mean, we keep saying it, but I really don't think they're worried about ruining HHN or Velocicoaster's hype right now. Summer peak is going to hit capacity a ton with the current setup and HHN will sell regardless coming off of last year. I wouldn't assume anything based on the opening date.
Even then, we had 4 house announcements between Hagrids opening date being announced and Hagrids actually opening and then had another house announcement only 11 days after Hagrids opened.
Things will happen when they happen. It's a weird year.