Well after having a good long look around and reading how you described Amber, i have come up with a few suggestions
If i were to chose a colour scheme out of the ones you have drawn i would chose pony 3
Reason: I think that the soft blue shows of her shyness while the black shows her thrill of discovery, curiosity and strong ideals.
Then again if your not sure the black would suit her personality you could always end her mane and tail with a nice orange or blue to mach her cutie mark.
I would give her the eyes you used on pony 1 and if i were to give her an element of harmony it would be kindness
Please reply and let me know what you think. I hope i helped