fading refers to changing from one color to another, no you can't fix it, it's genetics. Some fish are line bred to fade (red texas.) They start green and peel into red. Not all of them will fade though, only the winners. You never know what you're going to get with flowerhorns. With hybrids all your fry turn out a lot different.
nuchal humps (kok) are all in the genetics too. Some 1.5" sport kok's, some fish don't get them until 6". With your fish no one will be able to say when it will get it, it might never get one. If it has good strong kok genetics it will have it when small. With most flowerhorns though it starts to show between 2.5"-4". If it doesn't show one by 4" it probably won't have a good one.