Not to be inflammatory, but I wonder if the DreamWorks Land media reveal has something to do with the new release schedule, especially if the change happened last week.
Not to start a horse-beaten-to-death argument, but I know many theme park nerds (myself admittedly included) were a little disappointed with the immersive quality of DreamWorks Land. In the echo chamber of algorithmic social media, that opinion would likely get heavily amplified, especially when you consider that negative opinions often reverberate the loudest. This news will immediately get Universal-specific content creators talking about something else rather than dwelling on the new land, and create distance between now and the official opening of DreamWorks on June 14th. By the time it's officially open, DreamWorks Land will have the benefit of attracting the real children of tourists that would otherwise have limited entertainment offerings at USF, and the strategic reason for the land will become apparent to super-fans, regardless of actual quality. These announcements buy time.
It would make sense to me that Universal is attempting to steer influencers towards recollections of the beloved Slaughter Sinema to remind everyone "hey, we can make bangers, too", and to distract from some of the unfavorable comparisons to other themed entertainment news (Fantasy Springs, Tiana, Pixar Fest). It might be easy for some to compare DreamWorks to Pixar, but you simply can't compare Horror Nights to anything Disney is currently doing. I think it also remind everyone that Universal is edgy and can pivot, allowing them to have their cake and eat it too.
Knowing that a hand was forced by Spooky Empire to show something also makes me think someone in marketing was like "Let's keep going, this is working."