For the first two questions, you can only use four RGB values. So for example you could use $f5f5d4, $96cf85, $4b6d85 and $352b31 (such as in my display picture). No other RGB values should ever appear anywhere in the game. For the third question, no one will know you started early but it is very strongly against the spirit of the game jam. You are essentially cheating, and given it is an online competition with no prize you are only cheating yourself.