The style of building terms in this plugin is not translation friendly. Example:
__( 'General admin', 'peters_collaboration_emails' ) . '(' . get_option('admin_email') . ')'
is not nice. The current way shows "General admin(firstname.lastname@example.org)" without space between "admin" and "(". In every language. Better is
sprintf( __( 'General admin (%s)', 'peters_collaboration_emails' ), get_option( 'admin_email' ) )
Please, can you change the style for the next big release? There are few places you can improve. I can help you with testing, for sure.