These are all questions and fears that every person in AA had themselves at one time.
The types of meetings just refer to the particular topic. Any of them are appropriate to go to as a newcomer. The 'open' meetings just mean that they are open to non-alcoholics (such as nursing students for example) who have an interest in the program, but are not themselves seeking to stop drinking. All AA meetings welcome anyone who wishes to stop drinking - which is the only requirement for membership.
All your other questions will be best answered simply by GOING.
I understand your concern about being seen. Let that go. You are suffering... And rest assured that anyone you may happen to know who you see at an AA meeting will also be suffering or at least will understand your suffering. AA is anonymous and I have never seen it be otherwise. It has worked for nearly a hundred years for good reason.
You sound ready to break the awful chains of addiction to alcohol. I know how tough that can feel. Particularly so in Australian culture. I hope you'll go I've AA a shot.... You will find quickly that your fears are unfounded and what will greet you is an understanding fellowship of people who get it and who are there to help one another free themselves from the darkness of alcohol.