Like you, I’m guessing that it’s a plugin.
Maybe try deactivating some plugins to see if the post goes away?
Let me know what happens.
I’m sure there are multiple ways to go about this, but here’s what I would do:
1. Don’t link the domain to your host yet.
2. Just load the WP site to your host. Your host should have some sort of default domain for this situation. It will be like [something].[hostname].com
3. Once your client approves of the site, link the domain to your host.
Make sure the email isn’t in your “Junk” email folder.
This happened to me last week.
