Both were born in Singapore, both gained ROA by their own right, I believe the lady with *** has been living in HK for the past 14 years, and the guy married a HK girl and has been here for almost 10.
The "only" difference we could discern was the birth place of the parents. Been quite a topic during lunch, these stars!
I didn't think you can gain 3 stars by being here for any number of years. You said one of the parents was born in the Mainland. Did he hold a 3 star HKID card? If so, maybe HK immigration considered him "not settled" in Singapore, and thus was able to pass 3 star to the child even though the child was born outside of HK.
As for marrying a HK girl, that makes no difference. I'm a 3 star HKID holder (Chinese born in HK) and my wife is non-Chinese (she's a kiwi) and she has no rights in HK at all, apart from qualifying for a dependant visa. The same goes for my children who were born in Australia.
-titus