3. Wait until the teacher isn't looking, or they're preoccupied and then gesture for the guy next to me to move his paper closer to the edge so I can grab a peek. Or I just whisper/mime to them in search of the answer or clues.
Yeah, you can be failed on the spot for that.
lencake - Know the reading time thing? It's super useful!
Generally on any SAC or exam, the questions will follow a logical order. Use that order to your advantage. Figure out what questions are your strongest and your weakest, and you'll find it'll probably fit into that order somewhere, and answer the questions from strongest to weakest. That way, you get the easy marks out of the way first, and have plenty of time for staring blankly at the paper.

In terms of going further into the unit - go ahead. In terms of methods, most of probability is completely new content, but it's not really that hard, so why not get a head start, smash the competition?
I also see you're doing specialist - a lot of the upcoming stuff is pretty hard, except for mechanics. Mechanics is incredibly easy, and the reason why it's left for last is only because it's a logical progression, not because it's hard. So if you have some spare time, try teaching yourself the mechanics section. That way, when everyone else in your class is learning that, you'll just be revising, and will have more time at the end for harder topics, like modelling and diff equations.