Take it easy, it is nothing to worry about.
Each XF license can only be associated with 1 domain. So if you are gonna change your domain, change it and later log in into your customer account and update the domain. Done.
In Admin Control Panel in your XF installation, you can type in whatever you want. Nobody cares but obviously update it to the correct one. You don't have to change your email or homepage, all is up to you how you want it.