Happy - I'd think it should be pretty easy and simple to get your permanent HKID cards back. Just make an online appointment a few weeks before your planned return and then bring all the relevant documents to the office.

Having said that, a HKID card doesn't facilitate your visits to China, other than able to use e-channel to leave HK quickly. In order to get a Home Return Permit, you'll have to first apply for a HKSAR passport first. Just a HKID may not be suffice to apply for the HRP, at least when I checked for myself last time.

To apply for the HKSAR passport and subsequently the HRP is a declaration of being a Chinese citizen. Both of you should be eligible, since you were born in HK and China respectively. Whether that's what you want to do is a separate matter. Or you can just continue to apply for Chinese visas with your US passport. With your background, US$140 can get you a 2-year unlimited visa each time.