No one knows what will be required as yet. The earliest someone could apply would be the 27th November. And that’s if they got their visa on day 1 and are using an office that accepts 45 days prior.
800k 2 months prior to application and 3 months after. Then can drop to no less than 400k and has to back up to 800 2 months prior to next application.
US passport holders do indeed get a 60 day visa exempt entry stamp. They can extend that once for a further 30 days at a local immigration office.
Your airline however may ask to see an onward flight within the 60 days, regardless that you could get an extension. Some insist, some don’t seem to care.