How do I show inactive members in my BuddyPress members directory?

For current members:

BuddyPress will only show users in the members directory if they have  logged into to their account. You can get around this and activate all user accounts by installing and activating the Retroactive BP User Activity plugin.

If this doesn't work add the following to your child theme functions.php file:

update_metadata( 'user', '', 'last_activity', date( 'Y-m-d H:i:s' ) );

Remove this code once it has updated the last activity date for all members (when all members are shown on your members page).

For new members that register:

To automatically update new members in the members directory add the following to your child theme functions.php file:

function ghostpool_show_all_bp_members( $user_id ) {
    add_user_meta( $user_id, 'last_activity', date( 'Y-m-d H:i:s' ) );
}
add_action( 'bp_core_activated_user', 'ghostpool_show_all_bp_members' );