If I were you and had the capability to do it, i'd do the bachelor then masters. I think it's the best way to do things for a few reasons:
a) You get two degrees in the end - bachelor then masters.
b) You have a back up degree in case things turn south as a teacher.
c) You get valuable life experience - an extra 3 years of immersing yourself in a different discipline before deciding to start teaching.
A double degree could also achieve this. The key difference in my opinion is that masters degrees require a level of research whether that be a capstone, a literature review, mini thesis, etc. In my MTeach at Monash, I had the option of either doing a research unit which involved a thesis, or a specific study area with a literature review. Safe to say I had no interest in doing a Ed.D or Ph.D so I just went with the latter.
I personally opted for the Bachelor then Masters pathway because while I reeeaaalllyy wanted to be a teacher, I wanted the security of a back up in case things turned bad (safe to say they haven't, yet...) AND I also had three full years of focusing purely on the academic side of my method areas before I decided to go and teach it. In fact, I am really glad I chose this way because it allowed me to develop some very strong academic skills particularly in maths that I didn't have previously. I originally wanted to do business and computing as my teaching method areas but shifted around 1 semester into my comp degree to maths from business. So now I teach maths and computing.
I couldn't imagine myself just doing a teaching degree without actually doing that 3 year bachelor's degree first.
The real issue in my opinion is undergrad teaching degrees that aren't part of a double degree program - this severs any chance you have at learning real in depth content required to teach. Just because you learnt it at school yourself and did reasonably well at it, does not indicate that you can teach it well. It's a good start, sure, but it definitely is no significant measure. I have seen student teachers who are year 12 school leavers who personally have had great academic success yet (to put it absolutely bluntly) suck in the classroom - no rapport, no relatability, no enthusiasm for their subject matter.
btw, i actually heard from my mom's friend that unimelb are more for people to are looking into the research field because u have to write lots of essays and stuff, but monash is more practical so the students get more work opportunities and work on hands-on things.
Education is a discipline at uni that requires essay writing. There's no avoiding it. I did my MTeach at Monash and there were heaps. Expect it whereever you go.
tl;dr double degree or bachelor then masters. avoid teaching undergrad on its own. It'll pay off in the long term.
Anyway, happy to chat about it anytime feel free to reply or PM. Cheers