Are both David Cook and Steve Burns singers?
yes
Title: David Cook (singer)
Passage: David Roland Cook (born December 20, 1982) is an American rock singer-songwriter, who rose to fame after winning the seventh season of "American Idol" in 2008.  Prior to "Idol" he released an independent album entitled "Analog Heart".  This was followed by his post-"Idol" major-label debut "David Cook" which was released on November 18, 2008 and has since been certified platinum by the RIAA.  His second major album "This Loud Morning" was released on June 28, 2011.  His third post American Idol and fourth overall studio album "Digital Vein" was released on September 18, 2015.
Title: Steve Burns
Passage: Steven Michael "Steve" Burns (born October 9, 1973) is an American entertainer, actor, guitarist, musician and singer.  He is known as the original host of the long-running children's television program "Blue's Clues" from 1996 to 2002 and was nominated for a Daytime Emmy for his performance on the show in 2001.
Title: Andy Skib
Passage: Andy Skib (born November 9, 1985, San Diego, California) is the lead singer of the rock band Midwest Kings (MWK).  He spent most of 2009 on the Declaration Tour with "American Idol" season seven winner David Cook.  Skib has previously co-written songs with former David Cook bandmate Neal Tiemann, who also served as lead guitarist for their band, Midwest Kings (MWK).  Additionally, he has co-written songs with artists Zac Maloy (The Nixons), Hanson, Graham Colton, and Jaret Reddick (Bowling for Soup).  Skib is also known for his most recent solo project, To Have Heroes.  Skib is a member of David Cook's band, The Anthemic, providing rhythm guitar, keyboards and backup vocals.  Skib and the rest of The Anthemic worked on Cook's second album for 19/RCA Records.  The album, entitled "This Loud Morning", was released on June 28, 2011.
David Cook (singer) Steve Burns