Sure. I'm not saying it's not possible, but it's just more expensive to have a decent sized room to live in. Most people are living in small flats with their family. Expats usually make more, and can enjoy living where they want mostly within reason with some sacrifices (it's still life). But yes if someone likes a crowded super convenient living style, nothing beats Hong Kong. Higher cost of living kind of puts a damper on the quality of life thing. Eating out (western food) is so much more expensive whenever I travel now I feel like why's the nice michelin restaurant so reasonably priced? LOL. Anyway since OP isn't staying in HK forever, I do think it's a good idea. Career wise it'll be a little bit of a shock since it's not the same department (not sure how specialized what not).
There are still a lot of people who enjoy HK! We're all still here too lol.
Based on what I have seen, I would probably expect your salary to be lower. You are the one instigating the move, so the companies generally tend to low-ball the salary as they are the ones "doing you a favour". Obviously your relationships and connections within the company will come into play. You are also starting in a new role, so your current salary might not be taken into account. Given your age, experience and circumstances, I think they would probably offer you a salary of 20k, maybe even start off with something lower. I know that the locals at my company with a similar profile (age, experience) get around 15k.
I think before you make any decisions, you should see what the company can offer you. I would not move to HK for anything less than 25k a month if I was you. Life is doable earning less that, and many families live on far less, but your quality of life compared to what you have now won't be worth it.
One thing not to forget is TAX...Income tax. If you remain a resident of Australia for taxation purposes (check the ATO website about this), then you will need to pay income tax in Australia, as well as Hong Kong. Also, Income tax in HK is NOT PAYE, so be sure to set aside enough money to pay your first year's income tax, PLUS your second year's provisional income tax in Hong Kong. Trap for young players.