Have musicians Hansi Kürsch and John Reis both performed as members of a band?
Hansi Kürsch: Hans Jürgen Kürsch, better known as Hansi Kürsch (born 10 August 1966 in Lank-Latum/Meerbusch, Germany), is a German musician best known for being the co-founder, lead vocalist, co-composer, and lyricist of power metal band Blind Guardian. John Reis:  He is best known as the singer and guitarist for the rock band Rocket from the Crypt, which he formed and fronted (as Speedo) for the entirety of its career from 1990 to 2005.
yes