Hmmm, I wouldn't go for 1A/K personally. There isn't much room there, especially with a storage space between the seats. If you don't particularly care about having a windows seat, I'd go for the middle pair. 3E/F or 4E/F would be my pick. 2E/F are OK, but 2A/K may need to get into your space to reach the overhead bins.

I don't think there're arrival lounges in Sydney.

Lastly, welcome to Flyertalk.