Here's the link to Hong Kong's Immigration Department:

http://www.immd.gov.hk/ehtml/topical_3.htm

Did you apply for a "temporary" HKID card at your nearest British Consulate in America prior to July 1, 1997? Did you "renounce" your BDTC? Did you also register for your BN(O) nationality before July 1, 1997 since both you and your husband were BDTC? If so, you just need to take the "temporary" HKID card issued by the local British Consulate to the HK Immigration Department and they will process a permanent one for you.

If you did not, AFAIK, both you and your husband should still be entitled to obtain a new 3* HKID as I have a friend in similar situation did apply for a new HKID recently without any problem. However, I do not know the particulars of the process. Contact the HK Immigration Department at the link above for guidance.

I do not know the practice for China visa for American citizens. However, 3-year multiple entry visas are routinely issued to Canadian citizens with 3* HKID if you apply in HK.