sleepypiggy,
I apply for dependant visa for my baby 1.5 years ago. At that time my wife and I had no jobs. We had to proof to the immigration that we had somewhere to live and we had enough money to live in HK until one of us find a job.
So most important thing is as long you can proof to the immigration that you won't need any financial help from HK gov then you should be fine.
You can be a british citizen and a 3 stars HK resident, its no problem. Once you live in HK for over 7 years you can apply for the 3 stars HK residency regardless of your citizenship.
I hope this help.