Credited cast:  
Robert Hughes Ashley Wallace, the discjockey
Tom Oliver bodyguard, bartender & taxidriver
Bruce Barry radio station manager
Stig Anderson manager (himself)
Calvin Cross  
Ivar Dahlborn  
Harry Lawrence ticket scalper "ABBA tickets going cheap... 50 bucks"
Michael Manson hotel receptionist
Sandy Manson girl in box office "But you haven’t got a press card, and we’re all sold out"
Ray Marshall man in ticket office "I can’t let you in if you haven’t got a card"
Frances Mathews narrator, "The Girl With The Golden Hair" "From concert to concert, from town to town"
Thomas Minor musicologist "if you took an ABBA song apart"
Ake Olsson  
Karlene Rogerson hotel receptionist "I’m afraid so, they’ve just left for the airport"
Lena Andersson vocal backing group
Lena-Maria Gårdenäs-Lawton vocal backing group
Maritza Horn vocal backing group
Ulf Andersson musician, saxes
Ola Brunkert musician, drums
Lars Carlsson musician, saxes
Anders Eljas musician, keyboards
Wojciech Ernest musician, keyboards
Malando Gassama musician, percussion
Rutger Gunnarsson musician, bass
Finn Sjöberg musician, guitars
Lars Wellander musician, guitars
Uncredited:  
Wes Denbaum stage announcer "ten minutes and away we go!"
David Etherton news cameraman
Richard Norton bodyguard/fitness trainer (himself) "ich nee sum chi"
Bob Jones bodyguard (himself)
Paul Dainty man on phone (himself) "I just want to recheck with you on the arrival arrangements in Melbourne"
Thomas Johansson tour promoter (himself)

I'm trying to identify exactly who all these people who feature in THE MOVIE are.
 If you have any further information, please write to me.

Thanks to Mark Hannam, Gary Collins, Paul Carter, IMDb for additional information.