Hi Paulcut,
From my understanding:
1. You are confirmed at booking into A class, but you will need to ensure when you book that A class is available. If not, then you will either be booked into L class or you can choose another flight. If there is A class though, you will be confirmed and it is extremely unlikely you will be bumped and this would be for operation reasons (ie. change to a smaller aircraft).
2. You earn F status credits if seated in First.
3. Not quite sure, never had the chance to try them. Do check out some of the trip reports, I believe NM makes reference to them in his BNE-BNE the long way thread.
Hope this helps,
littl_flier