Removed the two lines from wp-config.php – a couple of things happened:
1) My website is now displaying as I would imagine a default install would.
2) My “Forums” subdir network no longer has settings for Buddypress (anywhere – including “Dashboard” submenu and “Settings” submenu); instead…
3) My “Forums” subdir now has the yellow bar at the top of the wp-admin, with “BuddyPress was successfully activated! Please run the installation wizard.”
Clicking that link gives me the message “You do not have sufficient permissions to access this page.”.