I think:
Violet Hill - The first single
Viva La Vida - it's doing better than Violet Hill...#1 in UK, US and AUS
Lost! - It is already successful on Itunes top 100 in UK, US(releasing it 3rd will do better than what Lovers would)
Lovers in Japan - i dont see this song doing well as the title wont make sense to listeners, release it 4th
Cemeteries of London - 5th single because the album is doing so well