I got my ATAR back!!!!! I'll list the subjects I did alongside the marks I got:
Biology - 88
Chemistry - 79 (rip)
English Advanced - 91
English Extension 1 - 43/50
Legal Studies - 92
Mathematics - 81
Studies of Religion I - 48/50
That gave me a 93.75, which I'm fairly impressed with considering I was saddled with two relatively average subjects. I took Mathematics Extension 1 for a while, but I realised it wasn't for me in the middle of the year after coming last (~10 marks behind second last) in a mid-year exam and being ranked last by an unrecoverable margin :(
Your subject plan would give you 11 units for Year 11 (you need 12) so assuming you pick Extension Maths you would need an extra subject altogether, which would give you 13. 13 units is a lot of work - I did 13 units in Year 11 - but they're survivable, and you always have the chance to drop a subject you don't like in Year 12!