That is what we ended up doing. For anyone in the same boat, we ended up using a role of "Pending" that was a duplicate of the Subscriber role.
[mb_user_profile_register id="meta-box-id" role="pending"]
Then as part of the approval process, the admin changes the role to "Approved" which has the capabilities we want, then we use another plugin to fire off the account activation and all of that stuff.
Thanks for the help!