1. Yes, but it's not foolproof. Much less than 1% chance Chase surprises you with a billing date change. For a Jan 6 statement date you pretty much have to take this chance, because reaching the threshold too close to the statement date often results in a one-month delay in posting the bonus. Something like 5 days before statement drop is a reasonable deadline for posting your transactions to meet the threshold.
2. 1 to 2 days, I think.
3. Should be 1 day.
Keep in mind that that this is close to the annual year end processing which can last a couple of days. I don't know but this year since New Years Day is on a Sunday there could be issues, and there is the new reservation system.