BuddyPress.org

Hmm… you shouldn’t need to add this to /bp-themes/bp-default/, if you upgrade, you’ll lose your changes. Try using the same snippets in Cosmic Buddy’s functions.php and header.php.

Anyway, Cosmic Buddy is not a child theme of the BP default theme, so I don’t see why it would work if you paste it in /bp-themes/bp-default/.