Question: Have both Peter Garrett and Kai Hansen been in the music industry?

Context articles: A Version of Now
Kai Hansen
Land of the Free (Gamma Ray album)
Roland Grapow
Keeper of the Seven Keys: Part I
Dennis Ward (musician)
Iron Savior
Peter Garrett
Gamma Ray (band)
Helloween

A Version of Now is the first solo studio album by Australian rock musician Peter Garrett, which was released in July 2016 on Sony Music Entertainment Australia.
 The album follows Garrett's retirement from Australian politics at the 2013 federal election.
Kai Michael Hansen (born 17 January 1963) is a heavy metal guitarist and vocalist.
Land of the Free is the fourth studio album by German power metal band Gamma Ray, released in 1995.
 Continuing a trend that would conclude with the band's fifth studio release, the lineup for the album was different from the previous one, as "Land of the Free" was the first Gamma Ray album to be released since the departure of Ralf Scheepers, leaving Kai Hansen to take up lead vocals.
 While not his first stint as a vocalist (Hansen had sung lead for Helloween until 1987 and had also recorded lead vocals on "Heal Me" from "Insanity and Genius"), it would be the first time he had performed lead vocals exclusively in 8 years.
Roland Grapow (born 30 August 1959 in Hamburg, Germany) is a professional guitarist and music producer.
 Grapow is best known for his time in the leading power metal band Helloween, who he played with for 12 years after replacing founding member Kai Hansen.
 He subsequently created the power metal band Masterplan in 2001, which is still active today.
Keeper of the Seven Keys: Part I is the second studio album by German power metal band Helloween, released in 1987.
 It marks the first appearance of vocalist Michael Kiske, and is considered the album that created the genre of European-style power metal.
 Kai Hansen stepped away from doing vocal duties as he had difficulties singing and playing the guitar at the same time during the previous tour.
 It was an album dominated by Hansen, due to an injury to co-guitarist Michael Weikath which prevented him from performing on much of the album. "
Future World" was released as a single and a music video was made for "Halloween" but with 8 minutes omitted from the song.
 The band originally planned to release "Keeper of the Seven Keys: Part I" and "" as a double album, but their record label refused, insisting that the albums be released separately.
 Much later in 2010, both albums were released together with bonus tracks.
Dennis Ward is an American bass player and music producer.
 He is known for his various works as a producer for heavy metal and hard rock bands in Europe, as well as for being the bassist and founder of the band Pink Cream 69.
 Dennis is also currently working with a band formed in with ex-Helloween members Michael Kiske and Kai Hansen called Unisonic and performs lead vocals for the AOR studio project Khymera.
Iron Savior is a German power metal band that formed in Hamburg, Germany in 1996.
 Following a period of several years working behind the scenes in music production, multi-instrumentalist and producer/engineer Piet Sielck joined with former Helloween bandmate Kai Hansen and then-drummer for Blind Guardian Thomen Stauch in a new project that would blend power metal with a high-concept science fiction story.
 The band's debut album "Iron Savior" introduced the story that would be told over the course of multiple albums, featuring a self-aware space vessel called the Iron Savior and its relationship to the mythical lost civilization of Atlantis.
Peter Robert Garrett {'1': ", '2': ", '3': ", '4': "} (born 16 April 1953) is an Australian musician, environmentalist, activist and former politician.
Gamma Ray is a power metal band from Hamburg, northern Germany, founded and fronted by Kai Hansen after his departure from the German power metal band Helloween.
 Hansen is the current lead vocalist, guitarist as well as the chief songwriter of Gamma Ray.
 The band is known as one of the most prominent bands of the German heavy metal scene.
Helloween is a German power metal band founded in 1984 in Hamburg, Northern Germany by members of bands Iron Fist and Gentry.
 Its first line-up consisted of singer and guitarist Kai Hansen, bass guitarist Markus Grosskopf, guitarist Michael Weikath, and drummer Ingo Schwichtenberg.
 After the release of a self-titled EP and their debut album "Walls of Jericho" in 1985, it expanded into a quintet with the addition of singer Michael Kiske, Hansen choosing to focus on guitar instead.
 Under this line-up, they released the "Keeper of the Seven Keys" albums (1987 and 1988), which established Helloween as a notable heavy metal band and led to the creation of the power metal subgenre.
 However, Hansen left the band quickly after the release of "Part II" and was replaced by Roland Grapow.
 He then created the band Gamma Ray.