Question: Who was the founding lead guitarist in the band whose single was used with "Bridge over Troubled Water" to create the charity single "A Bridge over You"?

Context paragraphs:
Bridge over Troubled Water (song): "Bridge over Troubled Water" is a song by American music duo Simon & Garfunkel.  Produced by the duo and Roy Halee, the song was released as the follow-up single to "The Boxer" in January 1970.  The song is featured on their fifth studio album, "Bridge over Troubled Water" (1970).  Composed by singer-songwriter Paul Simon, the song is performed on piano and carries the influence of gospel music.  The original studio recording employs elements of Phil Spector's "Wall of Sound" technique using L.A. session musicians from the Wrecking Crew.

So Long, Frank Lloyd Wright: "So Long, Frank Lloyd Wright" is a song written by Paul Simon that was originally released on Simon & Garfunkel's 1970 album "Bridge over Troubled Water".  It has since been released on several Simon & Garfunkel compilation albums.  It has also been recorded by the London Pops Orchestra and Joe Chindamo trio.  Art Garfunkel has stated that the origin of the song came from his request that Paul Simon write a song about the famous architect Frank Lloyd Wright while Simon has stated that he wrote the song, despite not knowing who Wright was.  Garfunkel sings lead on the majority of the song while Simon sings on the bridge.

Chicago 13: Chicago 13 is the eleventh studio album by the American band Chicago, released in 1979.  The follow-up to "Hot Streets", "Chicago 13" is often critically disfavored.  This would be the band's final release that features lead guitarist Donnie Dacus, who had followed late, founding lead guitarist, Terry Kath.  All band members would contribute to the songwriting (one of only two albums where this is the case, with the other being "Chicago VII").

Blackfeather: Blackfeather are an Australian rock group which formed in April 1970.  The band has had numerous line-ups, mostly fronted by founding lead singer, Neale Johns.  An early heavy rock version recorded their debut album, "At the Mountains of Madness" (April 1971), which peaked at number seven on the "Go-Set" Top 20 Albums chart.  It provided the single, "Seasons of Change" (May 1971), which was co-written by Johns with lead guitarist, John Robinson.  In July 1972 a piano-based line-up led by Johns issued an Australian number-one single, "Boppin' the Blues", which is a cover version of the Carl Perkins' 1956 single.

Coldplay: Coldplay are a British rock band formed in 1996 by lead vocalist and keyboardist Chris Martin and lead guitarist Jonny Buckland at University College London (UCL).  After they formed under the name Pectoralz, Guy Berryman joined the group as bassist and they changed their name to Starfish.  Will Champion joined as drummer and backing vocalist, completing the lineup.  Creative director Phil Harvey is often referred to as the fifth member by the band.  The band renamed themselves "Coldplay" in 1998, before recording and releasing three EPs: "Safety" in 1998 and "Brothers & Sisters" and "The Blue Room" in 1999.  "The Blue Room" was their first release on a major label, after signing to Parlophone.

Keep the Customer Satisfied (song): "Keep the Customer Satisfied" is a song by American music duo Simon & Garfunkel from the group's fifth studio album, "Bridge over Troubled Water" (1970).  It was included as the B side of their signature hit, "Bridge Over Troubled Water".  "Keep the Customer Satisfied" recounts the exhausting tours that Simon grew tired of, a similar theme to that of their earlier song, "Homeward Bound".

A Bridge over You: "A Bridge over You" is a charity single recorded and released independently by the Lewisham and Greenwich NHS Choir, the choir of the Lewisham and Greenwich NHS Trust located in south-east London.  It is a mashup of "Bridge over Troubled Water" by Simon & Garfunkel and Coldplay's 2005 single "Fix You", with additional arrangement by the choir's conductor, Peter Mitchell.  It reached number one on the UK Singles Chart at Christmas 2015.

Prehistoric Sounds: Prehistoric Sounds is the third album released by the Australian punk rock group The Saints in October 1978.  This was the final album to feature founding lead guitarist, Ed Kuepper, who left the band shortly after its release.  In October 2010, the album was listed in the top 50 in the book, "100 Best Australian Albums" with their debut, "(I'm) Stranded", at No. 20.

Let the Ocean Take Me: Let the Ocean Take Me is the fourth studio album by Australian metalcore band The Amity Affliction.  It was released on 6 June 2014 in Australia, 9 June 2014 in the UK and 10 June 2014 in the US through Roadrunner Records.  It is their first record to feature new guitarist Dan Brown following Imran Siddiqi's departure shortly before their previous album release (August 2012).  This is also the last album with founding lead guitarist, Troy Brady.

Oystar: Oystar are a folk / comedy English band whose single "I Fought The Lloyds" reached UK Top 40 singles in 2008.  The song was a cover of the song "I Fought the Law", with the lyrics altered to reflect a dispute over bank charges with LLoyds Bank.

Supporting paragraphs: A Bridge over You Coldplay
Answer: Jonny Buckland