Have you tried looking at the browser console? Open browser console first and then perform the function and see what it says if anything about an error. Even the server error log may show something.
You will not see your own new post unless you sort by read. You will see it when there has been a reply to it though. What you are seeing is the default behavior for this.
Buy license, install on localhost, setup how you want. From there, I do believe you can import into a live site. If things don't work out, XF will give refund in certain cases.
Not sure why you would expect trial forum software to have the ability to export settings. Demo's only last 7 days, you wouldn't have time to do extreme modifications anyway.
That would require a license transfer and there are certain requirements for that to happen.
https://xenforo.com/license-agreement/
How is that money grabbing???? Only one person can be the main account. Again, as long as the main account holder trusts you then they can give you their...