UNSW or USYD are your only real choices here. If you can get into either of their commerce or combined commerce degrees, go for it. I'm not saying the other universities are sub par or that their degrees are of lower caliber, I just think you maximize your chances of getting into the finance sector by attending those two universities.
The reason is that finance employers selectively target UNSW & USYD and even though they say all candidates are considered on the basis of their strengths, there is a strong bias towards those two universities. I have attended many interviews and have many friends and know many people who are trying to work or do work in the finance sector, and the message is always the same: of the student intake coming from Sydney, it is exclusively (with the very rare exception) from UNSW or USYD. Surprisingly, there are a lot of intake from interstate and even from NZ.
Also, do not be overly concerned with the specific degree or major you're doing. As long as you get into one of the two universities and pick finance as one of your majors, you are fine. Recruiters do not actually care about what you have studied or what program you are on, they are more interested in your experiences and your capabilities.