Arriving at the airport at 1:30 for a 2 flight is totally impossible. If your flight is at 2, I would arrive around 12:45-1. If you don’t have to check bags or do anything. If you have to check bags and get boarding pass, then 12:15-12:30.

US airlines board really early (like an hour) and KE/OZ just 30 mins before departure. That time of day isn’t super busy time, but 1:30 leaves NO time for delays in security. It’s also a 5-10 Min walk from the train terminal to the airport building itself.

If you have a US passport, there is no visa requirement. You get 90 says visa free entry.