I have found the lighter chicks end up being a lighter color with Carmel chest. The darker chicks end up being a little darker with chestnut chests. All crests are dark so far with one or two white dots, lol. I'm working on finding a hen that'd help with that.
Your down to feathers experience correlates with mine.
The striking contrast you are seeing between (neck) hackle feathers and the body is due to the influence of "cream"; those pullets/hens have two copies of the "cream" gene ("ig"=inhibitor of gold) which inhibits the expression of gold. So it would be accurate to describe the hackle feathers as cream.
As the Cream Legbars are a gold based bird, if the pullet/hen does not have two copies of the cream gene, then the hackle feathers are a warmer color - gold - and have less contrast compared to the body.
The dark crest is a separate element which is striking on its own. Sometimes the dark crest will spread down into the hackle feathers and mask much of the color, without regard to gold or cream.
Describing some of the feathers as caramel is yummy! There are also other ways to describe those influences. The Cream Legbar down pattern reflects a wild-type genetic basis. The chest color on the pullets/hens is referred to as "salmon", which is typical for a wild-type chicken. If the pullet/hen is cream, then the salmon color is a little washed out looking compared to a pullet/hen that is gold. There is also a red/chestnut influence which may make the area around the head, neck & crest a little richer chestnut (caramel =) color in both the gold and cream colored pullets/hens.
That's both fun and helpful to have updates with your customers. Have you found the Cream Legbar Club website? It will offer a range of appearance information that may be helpful as a breeder (Standard of Perfection - SOP).
I am interested to know other's experience with breeding away from dark crests, which are not correct for the Cream Legbar SOP. I have a sprinkling of hens that are cream with dark crests, and regardless of the roosters (which are unrelated and produce correctly colored offspring from correctly colored hens), I have not been able to eliminate the dark crest in favor of a lighter grey/cream/chestnut crest. It may take a few more generations but I enjoy the variations as well.