For ACST101, the small book "Mathematics of Finance" is worthwile it provides good study questions. However the big book "Financial Instruments and Markets" (forgot the exact name) isn't really necessary at all because the elements lecture notes are all that you really need. I literally did not use that textbook when i did ACST101 last year.
For BUSL100 - absolutely yes. You will need it for the end of year open-book exam. (well it's more than just open book they will let you take lecture notes and articles as well
we spent the last 2 weeks highlighting our textbooks for the material that will be in the exam)
For ECON111 you will also need the textbook, i wouldn't have survived without it.
For STAT170... you don't really need it but it is not useless I just studied mostly on MathXL.