I think that covered most of what you were asking if not let me know and I will try to answer if I have the info.
I think you have done a tremendous service to the diving community by posting here. I'm sure it has been difficult (perhaps helpful also) to replay and rethink your actions that day. You are a good writer, and your poignant account has prompted me to do a lot of reflection - and commit to future training for myself and family. Other contributors to the thread have said the same thing, so I imagine that countless other divers will also be improving their skills and attitudes. Thanks to you.
Your posts have been so thorough and detailed that I can imagine my husband and I in the same situation. And I can imagine that in the aftermath we'd have some stuff to work through. We came upon a car accident once (drunk meets bicyclist) and our inability to help left us with a mixed bag of emotions. I hope you and your wife will use this tragedy to make your skills and relationship even stronger (they are demonstrably excellent now) for your future dives together, getting help if necessary. We'd love to dive with you sometime.