Congrat on the upcoming 2nd adoption! GZ's very close to my hometown and Shamian Island is a beautiful place. Hotel-wise, I agree that the Holiday Inn is probably the only chain hotel in the area.

At first I did think about the Chase Priority Card (currently gives out 60k bonus points for uses on IHG group hotels, targeted offer is 80k and I heard it was open to everyone last month, not sure now). It has no foreign transaction fees, a low annual fee of $49 if you decide to keep it for future uses, and each year on your card anniversary, you will get a free night certificate for a 1-night stay in any of the IHG hotels worldwide. It can be a valuable card to keep especially your family will travel on a regular basis. However in comparison with Chase Sapphire, I would stick with the latter because the 50k ultimate rewards points worth more in general. Good advice from the other poster about getting Chase Freedom as a supporting card to pool reward points.
Yes you should be able to get your own sapphire card even though you are a current authorized user on your husband's sapphire card.

Also, if you are flying cathay from JFK to HK (my family often does), you may consider applying for any Citi AA card (there's a thread in this forum for the current 50k miles bonus + $100 off AA aifare? offer). BA's 100k miles offer was good until they changed their reward system into Avios points, which makes the redemption rate between east coast and Asia a lot higher than before. AA seems to be the way to go if you like to save up in their miles and use it for Cathay tickets redemption.

Good luck!