Yes. It used to be once the final milestone was reached the event was over, but now you have until the scheduled end date, which gives you until 3-6 hours before the daily reset later today to make sure your hours are counted.

Yes, and if you have any of the increase ARP % artifacts it would be a good time to equip them if you're still getting ARP from the event.

Thank you.

JOLLY GOOD ATTEMPT

The final midnight UTC update is unreliable. You should complete your hours by 2100 UTC today.