Yeah, it's exciting to hear about what else you have in store.
This pack really is kind of all over the place, so I'll just focus on one minor point: I don't share y'all's skepticism about the size of the Worlds Plaza. I seem to recall Worlds of Android saying what the total population was, but I can't seem to find it. I don't think it was too many, though, so we can safely suppose that 70 million people counts as "almost 1%." Worlds Plaza doesn't promise to hold them comfortably or even safely, so let's give each person two square feet of space. That's only five square miles.
Which yes, is still pretty big. But looking at the map, the plaza is served by two different light rail lines. And the preview for The Universe of Tomorrow said "Though it began as a temporary system, the expo has become a massive, important fixture in the southern California landscape...The expo grounds, themselves, are vast." So given the scale that these facts suggest, I don't think a plaza two-and-a-quarter miles on a side is too implausible.