users are sent "awaiting approval" and "confirmed" emails simultaneously

OK, I've taken these steps... but I'm afraid it still isn't quite right in terms of email notification only. I can see that, indeed, the user is created but not active in CB which is awesome! But the subscription itself becomes active, and so it seems we cannot therefore send a plan-specific email upon user approval in CB.

Is it possible for me to have the system check for the approval status in CB, as part of the subscription activation? It would great if the plan-specific email could be triggered when the cb user is approved in the backend.

(Note: I did not set the email as needing confirmation in this case, for other reasons.)

Thank you again!

You won't be able to do that with a free plan. Free plans instantly become active so they won't wait for confirmation or approval state as there isn't anything for the plan to wait on payment wise. This will result in plan activate emails being sent instantly. If the free plan is the only plan that requires confirmation or approval you could just put whatever notes you need in those emails within CB > Configuration > Registration and since paid plans auto confirm/approve they won't be sent those emails. Suppose this would only be an issue if you intend on having more than 1 free plan.