Thanks for posting all of those photos. It does not seem that there is a discernible link between down color and adult coloration from what I could see. I realize the sample size s small here, but are there any patterns you think have emerged?
Yes, I noticed a few things and was hoping others would too (even though I know that is really hard to do from photos).
1) I don't think that the hackle color of the mature cockerels has anything to do with the down color. This I feel is governed completely by the cream gene (two copies, one copy, or no copies).
2) Both light colored down chicks had lighter colored head/faces in the juvenile stage while both the darker colored cockerels had darker heads/faces during the juvenile stage. I think this will be true in a large sample population too.
3) Both the light colored cockerels had a lot of chestnut color in the Juvenile stage while neither of the dark colored cockerels did. I need a larger population to draw any conclusions on this. The two dark colored cockerels could just lack the chestnut modifiers but it is also very possible that the darker chick down covers some of the chestnut color during the juvenile development.
4) I no longer have the blond cockerel from GFF, so he didn't make any of the final evaluations, but from the juvenile evaluations and evaluations of the lighter cockerel that was in the final evaluations it appeared that the lighter color down cockerels have lighter chestnut saddles than the dark downed cockerels (even though one of the darker cockerels had too dark of a hackle and one seem to have the about the same color hack as the lighter downed cockerel). So...again I need a larger population to test my theory, but think that the lighter color cockerels will across the board have a less vibrant color on the saddles than the dark down colored cockerels.
5) I need to check the under color of these cockerels to see what color they are. I haven't done this yet but am guessing that the light color down cockerels will have a cream under color and the dark down color cockerels a gray under color
6) The final comment is more for pullets. It appears that the lighter down color pullets will produce tan to gray crests while dark colored down pullets will produce black crests. The cockerels showed chestnut colored crests (again like the saddles more vibrant on the darker down cockerels), but I can really say much about the cockerel crests since only two in the final evaluation had visible crests.
On a personal note, the "B" cockerel who was the dark colored down cockerel from GFF is the only one that I have breed at this point. He has produced 100% dark colored down chicks from crosses with a dark colored down pullet and 75% dark 25% light from a cross with a light downed pullet. all of the pullets have produced cresting even though the cockerel has no visible cresting. 
I can't wait to see what the other two cockerels produce. I will be doing a lot of Cream Legbar hatches this fall. 
