Tickets in hand

My flight is going to be pretty complicated...and long. I fly from Atlanta at 4:30pm on Friday, October 20th, stop in St. Louis, then in L.A. and then on to Brisbane. I arrive in Brisbane at 6:30am local time on SUNDAY, so, 4:30PM Saturday Atlanta time. I hope I can sleep some of that time. I also hope that I won't suffer earaches for the 12-hour hop across the Pacific. That would be extremely annoying.