Yes they can, no problem, they have unlimited work rights on this type of visa.

Yes they can, and this makes sense. The only issue is that when the fiancé visa is to be granted, the applicant needs to be outside of Australia.

You have 9 months from when the visa was granted to get married.

It's game over. The applicant will have to leave Australia and there are little, if any options open to a person that does not get married.

Yes, you can, however, you are a temporary resident so considerable costs apply.

No, you don’t. You do get Medicare at the lodgement of the partner visa though.

In the old days, maybe. A client could bumble their way through the process, and possibly eventually, secure the visa. It’s a bit like, I could, in theory, put new brake pads on my car. I can watch youtube, and ask a few questions. But would I? Of course not. Brake pads are important, and so is your partner. Get professional advice and save yourself a lot of hassle.