I will keep checking the chest and post updates as well as clues!
Clue: 20th June - No white! (3375 possibilities remaining)
Clue: 21st June - No yellow! (2744 possibilities remaining)
Clue: 22nd June - No magenta! (2197 possibilities remaining)
Clue: 23rd June - No brown! (1728 possibilities remaining)
Clue: 24th June - No light gray! (1331 possibilities remaining)
As of... 22:00, 24th June ...the items have been found! Congratulations freaksdesign!
The code was... Orange - Pink - Cyan
Somehow no-one noticed that I kept changing the spleef arena floor to these colours...