So, I turned the board active for about 30 minutes so I could try out different scenarios. It didn't come out the way I predicted.
1. Even if I changed Unregistered to zero permissions, I could register for membership and log in, but not see anything. If I want to register, I have to register with email. Email shows up with Member name on my Admin list of Users.
2. If I changed Registered (as well as Unregistered) to zero permissions, I could log in, but not see anything.
3. If I had a Charter Member with alternate group as "Registered", they were the same as #2.
4. I had to de-couple Charter Member from "Registered", and assign my dummy accounts to Charter Member, so they could get in and post. I created the users from the Admin panel.
This leaves me with.... I have to decide whether I want people to register even if the board is closed and they can't post?
Alternatively, I could make lemons into lemonade and go with @Mr. Lucky's marketing possibility: send a "open for business" email when the right time comes? I'd maybe want to put a suggestion to register in "the board is closed by under construction" message?
I also found out that no one except me gets access at all if I have a Home url. I removed that one in Basic Options. This made me feel super smart.
Advice needed.
My brain is getting frazzled.
Also, I have to seed the board with posts. Is there any way I can do that from the Admin panel? Otherwise, I have to log in and log out repeatedly using different user names (for the moment masquerading as Charter Members): it's a pain in the butt.