PS
In regards to cell phone usage in the Wizarding World, it should be maintained that a park is for fun, guest comfort, and safety first. Story elements may be disrupted by cell phone usage, iron railings in the halls of Hogwarts, noisy patrons, or even large visible show buildings, but ultimately guests are there to have fun and be safe and comfortable, so I would highly doubt there would be a no cell phone usage policy or even some sort of cell phone jamming device to sell everyone on being in Harry's world. Not saying they may not have written into the story of the Wizarding World something to counteract this apparent "plot hole" in the land, but I don't see them worrying too much about it. Besides, I have high doubts that Ollivander's won't be accepting mastercards and visas. Just enjoy the park, and don't worry too much on how truly "accurate" to the books Universal can be, it still has to be a park that operates safely, cost effectively, and does so 365 days a year. Besides all that, I'm sure you can find plenty of things far more inaccurate with the world then cell phone usage once it opens and you get to walk around and see it inside and out, and if you try to it may just hurt your experience. So just enjoy it when it opens and be thankful for the level of detail they have achieved.