San Japan emailed me back finally, a month after my initial questions.
So they said they'll be changing their wording to make sure people understand 3rd party administered OR supervised tests count. So the drive through walgreens ones will work.
Also Guests and Staff have to follow the same rules, so that means if any of them test positive within 2 days, they can't attend the event. (points of consistency, but that also means there could be staffing issues, or last minute guest cancellations)
They also said they don't have a broad sweeping basis for how to handle people who pay for a badge, but then get a positive test right before the weekend, as it has to be on a case-by-case basis.
I'm assuming it's because if you travel down and then test positive when you arrive, you are more likely to get a refund since you're already losing a lot of money for travel, but I'm guessing if you test positive the week of the event they'll just try to roll the ticket over to next year. Pure speculation though.
Oh, and they said they only listed the vaccines their attendees mostly used, not the full list. Which is of course a lie, because virtually no one in the US has astra zeneca. So unless they have a large mexican attendance (which I guess they might) it's probably just that whoever was writing it literally didn't know about the other vaccines. But they said they'll add any new vaccines to be approved as soon as it happens, but I'm guessing they'll only add ones readily available in the US. So if you're waiting for Novavax, you might still make it.