Thanks so much for providing these requests! We agree with you that these would all be great fields to have in custom reports. I want you to know that we've taken note of your requests.
Ultimately we have a lot things we would love to update with Custom Reports, and these fields would be great to have here as well. We'll keep you updated as we add new features to Custom Reports!
It would be super helpful to have additional fields such as the "Reporting Group", "Last Login" (date they last logged in to their learning account) and "Certificate Date" fields as options to add to custom reports built in the Custom Reports tool.