Have singers Lajon Witherspoon and Marc Bolan both been members of a band?
yes
Title: Great Jewish Music: Marc Bolan
Passage: Great Jewish Music: Marc Bolan is a tribute album featuring the music of English singer/songwriter Marc Bolan of the band T.Rex.  Produced by Danny Cohen, it was released on John Zorn's label Tzadik Records in 1998 as part of their series on "Radical Jewish Culture", following similar prior tributes to Burt Bacharach and .
Title: Marc Bolan
Passage: Marc Bolan ( ; born Mark Feld; 30 September 1947 – 16 September 1977) was an English singer-songwriter, musician, guitarist, and poet.  He was best known as the lead singer of the glam rock band T. Rex.  Bolan was one of the pioneers of the glam rock movement of the 1970s.  He died at age 29 in a car accident a fortnight before his 30th birthday.
Title: Lajon Witherspoon
Passage: Lajon "LJ" Jermaine Witherspoon (born October 3, 1972) is an American musician best known as the vocalist for the Atlanta-based alternative metal band Sevendust.
Marc Bolan Lajon Witherspoon