Welcome to the Land Downunder!!
Yes I'd safely say brothels her in Oz have showers in almost every room. It is usual practice to shower before hand and mouthwash for the girls protection and yours truly. Last thing you want is the previous punters germs all over yours (which could create a new type of virus or bacteria).
Regards to Japs and Koreans... In my experience they are just more pedantic about hygiene. But since it's a brothel normal practice is that all customers will have a shower anyhow. Before and after the session.
Time starts once you walk in the room.
Hope this helps in your punting future in Oz land.