I'm trying to study for my Stage 2 interview, but I have no clue what to expect. Is the actual interview basically the same as your stage 1 plus a teamwork exercise and math test?
Yes, I think the range of questions in the Stage 2 interview will be similar to the ones I encountered in Stage 1, though they will probably delve much deeper into individual topics. Remember that the whole purpose of Stage 2 is to gauge your technical aptitude, so all the exercises will be geared towards that purpose. Technical questions will be much more in-depth, HR questions more sharp-ended... you know the drill. Just study as much as you can.
Obviously there are other exercises as well, from the top of my head there is a group exercise, flight planning exercise, personality test, and math test as well. Stage 2 is the same for everybody so your itinerary will be the same as mine. Hope this helps.