Like Jazz519 said I think you can handle Extension Maths, even if you aren't in the recommended percentage, just try it out and maybe you'll be one of these students who performs better at 3 Unit Maths than 2 Unit Maths (funny thing lol but there are people like that). Extension Maths will just be like an upgraded version of normal advanced maths with probably much more homework and mathematical concepts but I'm sure you can handle the workload.
As for English take Advanced over Standard because it's hard to get a band 6 in Standard as Jazz said above, but in terms of the workload and difficulty, there isn't much difference, both types in my own grade have similar assessments, except with the percentages but honestly it's just a little bit harder and even if you are a low B, maintain that low B and maybe even turn that into a high B or even an A.
You've got your Business Studies and Economics, perfect if you truly want a career in finance and commerce and that sort of stuff, the two have similar concepts that can be applied to both subjects and make sure to brush up on your essay writing skills and your ability to remember the content and be able to answer the questions properly, no point in remembering the content if you can't apply it (insert finger pointing to head meme)
So you've got Ext Maths + Adv Eng + SOR + Business + Eco + final 2 unit subject
That remains Chemistry/Physics and Legal Studies
Of the two sciences, I'd probably take Chemistry because imo, I think Physics is the Maths science, Bio is the English science and Chemistry is both Maths and English, I don't know much on this unfortunately but just remember that in science it is not like normal Humanities where you got marks by regurgitating information but more like you must remember specific terminology to get full marks on the question.
Whilst I take Legal Studies (this subject is imo a bit of common sense like knowing court personnel, crime, human rights, rights and responsibilities, legal system and is based off typical multiple choice, short answer and essay, I think it's interesting and is a good indication if you want to study law or not, but is not necessarily how law will be like, it is like a simplified version of law itself).
I myself, I do think it's advisable to do at least 1 Science and in this case Chemistry, taking Legal would mean you have like 3 Humanities and no Sciences but if you're more of a Humanities person then go right ahead but I'm sure Chemistry will be a good refresher from the constant essay writing and short answers that you may get from Business and Economics.
But yeah that's what I think you should take but good luck in the future and hopefully you choose subjects you love and have interest in.