OK, I fixed this one. Here's the way it works now, when a brand-new member makes their first post:
1. They are shown a message that says: Your post has been submitted, and is being held for review by one of our moderators. Once your first post here is approved, your account will be unrestricted.
2. The timer on this message screen is now set to 20 seconds (it was 10 seconds which seemed a little too short)
3. Once a moderator or Gatekeeper approves the post, they get an email saying that their post was approved and their account is now unrestricted.