Depends on your goals. But in general I would say health and social behavior, as it can be very annouing to have a little raptor in the flock.
It is often described, that only looking on meat and egg ratio can produce very agressive birds.
As the celadon gene is rezecive you may have one or more heterozygotic birds in a flock, which lay normal eggs.
It is a mutation, quite rare yet, but not related to a specific color. All colors can be a Celadon mutation. So there is always the possibility, that your flock has one or more birds, carring the rezecive gene.
Do you want to breed to celadons?
Celadons are more and more popular ... an interessting breed project.
As said before, there are some colors having some issues. I don't know all ...
but e.g. the lethal factor, high lethal rate on pure breeds, at yellow (gold) and cinnamon.
Also red eyes, very sensitive to light like albinos, even as adult, also at cinnamon.
But many tribes are breeded to minimize these defects, ... so most cinamons have black eyes today, e.g. .
I am using for my cortunix chicks half square meter cage, 100x50cm cage with 30x30cm heating plate, for 30 quail chicks and a three-quater square meter cage, 120x60cm cage with 40x40cm heating plate, for 40 quail chicks. This works for about 2 to 2,5 weeks, maximum 3 weeks, then it is way too small.
I would say, yes ... I am starting with 4 blood foreign tribes. Guess 6 holds a bit longer
Also curious.... I will let you know when I am at the end with my 4 blood lines

No Clue. I haven't had so many generations to give any advice.
Cheers and good luck
Fenrisulfr ... on day 8 of "spring 2020 Cortunix Japonica hatching"