Howard is okay; definitely some weird questions here and there where it seems like non-NESA style questions, but this is to be expected for a textbook written by a single person. I watched lots and lots of Eddie Woo videos, and completed the entirety of complex numbers in two weeks with his videos just so I could take a breather in the first term. My school did complex numbers then proofs, but lots of schools (and i believe this is the NESA-rubric) go proof then complex.
In this case, you may end up feeling incredibly challenged. Proofs is probably the hardest topic, and again, I'd suggest you watch some Eddie Woo videos, and after you have become comfortable, take on the Cambridge, then Terry Lee exercises.
Beyond this, after you have learnt, probably up to vectors, you can start completing some trial paper questions/hsc questions. The real only way to get good at trials/hsc, is completing trials/hsc. While Cambridge and Terry Lee will definitely give you some great skills, HSC questions are often formatted, and arranged differently.
Get ahead and complete your notes/knowledge on Complex + Proofs. If you want, make a mistakes book, but I found that I never ended up reading back on my mistakes and it was a waste of time. Rather; when you get a question wrong, make sure you leave that question feeling 100% confident in completing it the next time you face it. MX2 is much more of a grind/building subject then MX1. in MX2, you are sure to leave your exams unsure, at times anxious, and leaving morning lessons dissatisfied with your understanding, and this is perfectly normal.