Re: admin email change
My guess is that the email in the config.php is used for setup only. Afterward, I changed mine in my profile and it gets updated in my WordPress user table. I changed the email address in my WordPress user table, and it’s changed in the profile in bbPress. None of those changes affected the setting in config.php. I requested a new password with the forgotten password link, for admin, and it went to the email address in the user profile, not the one in config.php.
I am pretty sure the email that is used on an ongoing basis is the one in the profile, and the one in config.php is used for setup only.
That’s my best guess. For consistency, I think I would update both, even if only so that when you do an upgrade in the future, the one in config.php is still accurate.