Here is a list of all the cousins and when they were introduced.
Any errors? Contact vix.

Ace - :ace - KD
Ban-Ban - :banban - MMK
Beyond - :beyond - WLK
Can-Can - :cancan - WLK
Colombo - :colombo - KD
Daisy - :daisy - WLK
Dipp - :dipp - KD
Drooby - :drooby - WLK
Foomin - :foomin - KD
Fujio - :fujio - KD
Hans - :hans - MMK
Harvest - :harvest - BK
Havana - :havana - KD
Honey - :honey - KD
Huey - :huey - WLK
Ichigo - :ichigo - KD
Johnson - :johnson - KD
June - :june - KD
Jungle - :jungle - KD
Kenta - :kenta - MMK
Kinoko - :kinoko - WLK
Kunihiro - :kunihiro - BK
Kuro - :kuro - KD
Kyun - :kyun - BK
Lalala - :lalala - KD
L'Amour - :lamour - WLK
Lucha - :lucha - WLK
Macho - :macho - WLK
Mag - :mag - BK
Marcy - :marcy - KD
Marny - :marny - KD
Miki - :miki - WLK
Miso - :miso - KD
Mu - :mu - MMK
Nai-Nai - :nainai - MMK
Nickel - :nickel - KD
Nik - :nik - KD
Norn - :norn - MMK
Nutsuo - :nutsuo - WLK
Odeko - :odeko - KD
Odeon - :odeon - WLK
Opeo - :opeo - KD
Paula - :paula - MMK
Peso - :peso - KD
Pokkle - :pokkle - MMK
Prince - :prince - KD
Princess - :princess - BK
Pu - :pu - BK
Ryu - :ryu - BK
Sherman - :sherman - BK
Shikao - :shikao - KD
Shy - :shy - WLK
Signolo - :signolo - WLK
Slip - :slip - WLK
Twinkle - :twinkle - WLK
Velvet - :velvet - KD