In order to satisfy the breadth component of your degree, you need to take a min. of 75 points (6 subjects) outside your faculty. At least one of these subjects has to be a level-3 subject. These usually have prerequisites. With your other breadth subjects, you should use them to fulfil these prereqs. For example, in order to do taxation law, you have to do corporate law, and in order to do that, you have to do business law. Just make sure you have enough space to be able to do that level-3 breadth subject.
For eco you need:
intro micro
intro macro
inter micro
inter macro
intro econometrics / QM2
micro
macro
econometrics / basic econometrics
level-3 economics elective (if you want to do honours)
For marketing:
Principles of Marketing
3 level-3 marketing units
9 + 4 = 13 for your majors
additional compulsory subjects: 2 (QM1, Org. Behaviour)
core program electives: 2 (taken from your first year outline)
mandatory breadth: 6
2+2+6=10
10+13=23. Hey, you've got one to spare!
EDIT: Didn't see the finance part.
Finance:
Finance 1
Business Finance
Investments
Corporate Finance
Derivative Securities
9+5=14
14+10=24 units. Hey look, it just fits.