There's less than a couple dozen CN based currencies. See http://mapofcoins.com/bytecoin.
Shadowcash tried to implement ring signatures on a Bitcoin code base. See https://shnoe.wordpress.com/2016/02/11/de-anonymizing-shadowcash-and-oz-coin/.
To my knowledge, no non-CN coin uses Cryptonight. -- Oops, I misread that last question, see lethos3's answer to that one below.