Ok I think your a bit tangled here.
Firstly I know a few people who were in your position, had 99+, didn't want to waste it, and some when Comm/law just because. 1 of them is doing well the other 2...dropped back to a single B.Comm. I really recommend just going single B.comm unless you feel like Law is your thing or your interested, don't do it for the sake of it, law is consistantly hard, and unless you wish to spend half your degree time on it just because "it helps you with tax accounting" ,just don't do it.
From what I've read, Commerce (international) (unlike the name suggests) doesn't really help you get "international" positions with embassies and stuff. The only thing is that you have to do 1 year of exchange, and although that can help in an interview, it's not such a signifcant factor for your job prospects,you'll be better of saving that one year advancing your career. Do it only if you really wish to go on exchange, otherwise you can still apply for exchange with a single B.Comm if your mind is waving around it.
You CAN do actuarial studies/ economics, and then pay to do all the other units required for a CA but there'll be still a signifcant amount of units left, and the price can be hefty(I heard you pay full fees). And then you would have to justify in each interview why you didn't just do an accounting major if your keen on doing a CA with the firm.(and accounting for that matter). Actuarial studies/economics leads to different jobs, if your keen on accounting switch one around with it and your set. Accounting is definitely a helpful major not just for accounting but it compliments many other jobs too related to Commerce majors.
If your dream is to work in a place "like the stock-market" then you might be looking towards being a trader,stock-broker, private equity, investment banking and the like.(have a search around google for these kind of jobs and read each description to see if any of them fancy you). All these jobs relate to doing a finance major so I suggest to take a look at doing a finance major as one of them, it's also the other "broad and useful" major in commerce, rivaled by accounting. This is why you see the most popular major combo being Accounting/Finance because they are both broad and useful in many jobs. Especially towards jobs involving the stock-market.
You have to realise Accounting and Finance jobs are two different paths. On occasions people do go into finance from accounting(not so much vice versa,because you have to do your CA,and job experience etc..and it isn't done as much), but that's usually because they had a sudden change of mind,and worked hard to stay relevant in interviews.
Consider what you really want to do,I do recommend Accounting/Finance as your two majors instead of Actuarial studies/economics, as the latter doesn't have as much real relevance to both paths you wish to take(and these majors tend to be for people who wish to do Actuarial/Stats/Economists). I can see that your probably trying to use your strength in maths also by picking these two majors, but please don't think as such, the jobs these majors lead to are different(although for the finance jobs you can get away with doing those majors as long as you know what to say in your interview(and have good marks), and you can always take harder math courses for finance. Actuarial especially can be a WAM killer if your not set on doing it.
Accounting and Finance majors allows you to take a shot at stock-market type jobs, whilst also allowing accounting to be a backup incase you don't make it.(or if you just wish to do accounting in the end)Because these jobs tend to have a high WAM recommended, usually Distinction-High Distinction +, whilst accounting tends to be a bit more lenient on the WAM and looks more at you.
