Old thread alert but a question that keeps coming up.
There are many part-time live out helpers in HK. Their number is growing especially as many who had Western employers (who have now left HK) were released but still have unexpired contracts. They tend to have a half dozen or so jobs on the go at once so unless you invite one to stay in your home you are unlikely to be the only one to get into trouble (the other employers will as well).
In my experience, however, any trouble you encounter will be as result of the helper falling out with another girl over money and the other helper reporting the girl. Do not in any circumstances employ a girl who has no visa (effectively an overstayer). Some of the girls who tell you they 'live out' have effectively overstayed.
The way I get around this is to come to an arrangement with a friend who has a legal helper to let their helper do my laundry/ironing on the employer's premises. I give the employer extra money which he gives to the girl as part of her salary over and above the norm.
Can't help with the cleaning, I'm afraid. Maybe you just have to do that yourself! HK apartments are small. It doesn't take long.