Is Casey Lynch a real person

Yes Casey Lynch is a real guitarist and a character is based on her in guitar hero 2 and 3

• A veteran of the tour circuit, Rocker's dirty, bass-driven sound and ultra-heavy riffs have influenced budding shredders from Maine to Alaska. She's tough, she's brash, and she'll break your heart faster than an A string. - Guitar Hero II in-game bio

Finally embracing her feminine appeal, Casey has risen to the status of 'Goddess of Rock'. When asked by a reporter if she had sold out, Casey replied with a roundhouse to the face. 'Don't worry, I'll pay the medical bill.'
in matter of fact i am associated with a casey lynch which resides in Kettering. He is a canny lad who no one really likes. He also has a humoungus left testicle due to a hereditory disease

source-I licked his balls twice