That's entirely too close to the most likely grand opening date of around June 17th, if you base it on the fact the original Wizarding World opened June 17th, 2010, and the big media only event was the evening of the 15th. You may be right in the middle of all that for Daigon Alley. If that date DOES get announced, very likely all rooms will be immediately booked up.
With educated speculation, it does make some sense the soft target for opening would be the 4th anniversary, so based on that STAY ON SITE, grand opening day it may literally be impossible to get into the studios until very late in the day.
People were lining up at IOA the night before for the grand opening last time, and they stopped letting guests in the park around 7-7:30 am until others left, and yes the park's official opening wasn't until 9AM that day, but they let people in to line up MUCH earlier, and that line snaked through the entire park and out the front gate all the way back to the theaters at Citywalk.
I was there, we lined up at the end of Jurassic Park, but bailed to watch the ceremony at the screens they set up at port of entry. I walked back to see the lines outside the front gate, and remember being shocked at how many people were still out there. They were snaking people through everywhere and the line still went on.
I have never seen anything like it before or since. If it's even half as busy as it was then for Part 2, stay on site, while you can, is most assuredly the better option.
