Fake American: Rael, the protagonist in The Lamb Lies Down On Broadway. A half-Puerto Rican street kid from New York City would be unlikely to refer to money as "notes and coins". But he does anyway. Also in the song "Back in NYC", Rael says "you progressive hypocrites". An American (of the time, anyway) would probably have called them "liberal hypocrites".
The evangelist charcter in the video for "Jesus He Knows Me" has a Deep South accent, at least until accent slips.
Which leads to a very interesting possibility of what "Me and Sarah Jane" is about...
The Pete Best: Anthony Phillips, who was replaced by Steve Hackett, and all of the pre-Collins drummers.
Ray Wilson also to an extent, as his career with Genesis was killed by fan indifference before it could begin. However at the same time, he has seemed to parlay that brief time into a substantial career, still performing songs from Calling All Stations live and appearing as a guest singer at Steve Hackett's 2013 Genesis Revisited II show at the Royal Albert Hall.
What Could Have Been: Celebrated indie songwriter/musician Kevin Gilbert, who had much respect and love for the "classic" Genesis (he performed the entire "Lamb Lies Down" album live on stage), was invited to an audition to replace Phil Collins in 1996. Unfortunately, he (Gilbert, not Collins) had died just a few weeks earlier. There's not telling what a talent like Gilbert could've done to invigorate the band.
When the band was forming ideas for what would become The Lamb Lies Down On Broadway, Mike Rutherford suggested composing a song cycle loosely based on Antoine de Saint-Exupéry's novella The Little Prince. Gabriel opted for an edgier, more Americanized concept album instead (The Lamb). While not used then, eventually these themes would lead to songs on 1978's ...And Then There Were Three... and prominently in the song cycle that book-ends 1980's Duke.
Casual considerations to replace Steve Hackett as guitarist in 1978 were rumored to include Jeff Beck, Robert Fripp and Steely Dan veteran Elliott Randall. It was later agreed to keep it a three-piece in the studio.
Among the people being considered to replace Phil Collins as lead singer was Fish, who had previously done vocals for some of Tony Banks' solo material. "Generillion" might very well have been really awesome, especially since Fish's vocals have been compared to Gabriel's to begin with.
Their 2007 Turn It On Again tour started as an attempt to reunite Banks, Collins, Rutherford, Gabriel and Hackett to perform The Lamb Lies Down On Broadway; when Gabriel decided against it, the three-piece band reunited instead.
Attempts were made to make a movie out of The Lamb since the late 1970s, but nothing came to fruition.
Abacab was originally planned as a double-album. Most of the tracks ultimately removed (most notably the instrumentals "Naninanu & " Submarine") appeared as B-sides, and the song originally meant as the album's closer, "Paperlate", eventually appeared on 3x3 and Three Sides Live.
Several tracks on Duke were meant to be a Supper's Ready-like suite taking up one side, yet in the end the band decided to steer clear of anything too similar to the dying genre of Progressive Rock, being as it was 1980. The band did perform the "suite" live in its original format and order during their Duke tour.