- One of them should be enough, seeing as though the syllabus specifies one
or the other.
- Crashing is not in the syllabus as far as I am aware of. (It was probably just taken over from the corresponding VCE publication, since they do examine it.)
However: A second opinion from a student would be extremely helpful here. 
- In theory, you definitely cannot count on it. But in practice, because it's the first year like you said it will likely be played down somewhat at least. NESA has generally been known to be friendlier on new things in the syllabuses wherever possible.
- If by "outcome" you mean the things starting on page 17 on the syllabus well of course you'd expect to assess all Year 12 outcomes. But if you mean the actual syllabus points for the topics, being realistic a 2.5 hour exam isn't enough time to assess each and every one of them...
But of course, you don't know what's
not tested in your paper until you actually see it.