Safe and comfortable viewing points for Sydney NYE fireworks [closed]

A Japanese friend living in Sydney and her sister, who is visiting Sydney from Japan for a handful of days, are going to watch the New Year's Eve fireworks, and I'll be accompanying them.

Unfortunately, I have zero experience in choosing a good spot for fireworks, as I assume they're so popular that it'd be too much of a bother to watch them!

The requirements I have are as follows:

1. The place should be reasonably safe. I'm not concerned about theft (if it happens, it's not the end of the world), but I am concerned about physical assault and sexual harassment, because as an Australian I don't really trust Australians or tourists when they've had too much to drink and are in a large crowd, and have some recollections of news articles about incidents happening during large events in Australia and other western countries.
2. It shouldn't be too crowded, or fill up too quickly.
3. Although not a hard requirement, I'd prefer something that's free. Not because I can't afford to pay for tickets, just a personal preference.
4. We want to watch the midnight fireworks, not just the 9pm ones.

None of us are disabled, and we're happy to choose an alcohol-free zone if necessary for safety. We're happy to put up with the presence of children, and getting front-row seat views of the fireworks aren't a top priority. The friend speaks some English, but the sister doesn't, though she's travelled overseas before.

When looking for information on suitable points, most of the guides seem to cater to those wanting spots with the best views, without taking into consideration crowdedness and the like. The only site that comes close to evaluating the sites and giving warts and all information is the official website by the City of Sydney, which has information such as whether they're ticketed, how quickly they fill up, and whether they have limited views of the fireworks. They also have a list of recommendations based on what kind of person you are, such as a list of family friendly vantage points.

We're currently looking at Ball's Head, which has the disadvantage of having limited views. Are there any other points where we can do markedly better, given the requirements listed above? Also, is it accurate to assume that there's going to be an inevitable trade-off between the quality of the view, versus how crowded, filling up rapidly, or expensively ticketed it is?

Update (can't post as answer as it's closed): We ended up either at Ball's Head, or a location nearby. It turned out to be fairly crowded, but it was apparently in an alcohol-free-zone, and the crowd was well behaved, and we were able to see the fireworks clearly. We watched the 9pm fireworks via the internet at my house.