It's a sex linked recessive like roux. SLB roux, and ginger are alleles, and there's an order of dominance involved in phenotype expression (SLB > roux > ginger) meaning SLB and roux males can carry ginger silently. I don't deal with it personally so that's kinda where my knowledge ends. As far as I know, there are no genetic issues with ginger.
Celadon is the one that most people get wrong. There's a LOT of incorrect info being parroted about it.
It DOES NOT turn the eggs blue. It removes the outer coating of protoporphyrin (the dark spotting and base coat), revealing the color of the shell. But if you want nice blue eggs, you are gonna be working for them constantly. You CAN line breed to get all birds that lay nice blue, but it takes generations. What you get from a breeder won't likely be that- they will (hopefully) select the nicest blue ones to send, but that doesn't mean their line is throwing that color consistently. Celadons are the hardest ones to keep a nice line for, because you're selecting for everything you'd normally have to select for (health, temperament, type, size, color, etc) and adding in the egg factor.
You're gonna hear a lot of people talk about "bases" and your going to have to rewire your brain to understand what they're talking about is pattern. Patterns can appear in multiple colors. Pattern is how the color is displayed, the shapes of the color. Fawn is a pattern. Sparkly is a pattern. I'm pretty sure pansy is a pattern (I don't know much about pansy.... It could be a morph, which is a phenotype name not necessarily a gene name... There are also two kinds of pansy and I don't care enough about them to find out what the difference is for sure but I think one is a gene and one is a multi-gene morph... you might want to ask which it is before getting them, because there's a big difference between introducing one gene and introducing multiple genes together). There are pattern mutations and color mutations. A "base" when referring to phenotype isn't a thing. People are always talking about a color or a pattern when they say base.
This is a REALLY IMPORTANT thing to rewire your brain about. Because you're GOING to see people who don't know what they're talking about yammering about bases, and it's going to be REALLY CONFUSING compared to just calling it a fucking pattern, or talking about the genes themselves. "fawn base" is meaningless. Het fawn tells you the bird has one copy of fawn. Homo fawn tells you it has two copies. Understanding it's a pattern and not a color means you will understand it can come in other colors. Understanding it's a pattern and not a color means you will understand other patterns can interact with and change it. Knowing sparkly and fawn are both patterns makes it easier to understand that the sparkly pattern is changing the fawn pattern, but that the color is not affected. Understanding that fee is a COLOR not a PATTERN (and what the color DOES, which is reduce/eliminate most reds in the pattern, possibly yellows as well in homo form) will help you understand why a fawn bird:
turns into this when fee is added:
That's still a fawn pattern, and you can see the similarity. But it has no reds because the fee eliminates them. It's not a "base" it's just a pattern.
Patterns can also interact and co-express!
here's the fawn pattern interacting with the sparkly pattern:
That's not "sparkly on a fawn base" it's just a co-expression of two different patterns.
It seems pretty obvious in these two examples, because they all LOOK like fawn. Describing it as a "base" might seem to make sense looking at those two examples. Describing it as a base makes way less sense when you know this is also fawn (I think):
Now you're up shit creek without a paddle, because what the fuck is that, it doesn't look at all like the other fawns. But understanding that this is homozygous sparkly fawn, and understanding that both are patterns and that this is what sparkly does, will help you parse what's going on when you look at the birds. This is also sparkly, but not fawn, and also isn't EB:
And while there's enough of a difference to be able to tell, talking about fawn as a "base" like it's a foundation is. kind of meaningless in the end. It's actually SO meaningless a term that you're ALSO going to hear things like "fawn enhanced." Which is another (imo stupid) phrase that shouldn't exist, that just means the bird also has signs of having fawn genes. EB can be "fawn enhanced" and it is the most pretentious way of saying the bird also has fawn genes.
I don't bother trying to argue with anyone in the quail groups about their language use. But it's needlessly confusing, imo, and understanding why is important to actually understanding what's going on compared to trying to memorize practical knowledge.