Where are you Cream Legbar chicks from?
There are been some really strange colors coming from one of the Ebay auctioneer's hatching eggs including yellow, tan, brown, red, gray chicks. If you got the chicks from that sources I have not idea what they will look like since the grown out birds from that source look just as strange.
There is also one of the Greenfire lines that produces blond male chicks. Everyone that I know that got the blond male chicks got them directly from greenfire and they were banded yellow. I got one of these male chicks.
I think the yellow chick down is similar to the difference between a light Norwegian Jaerhon and a dark Norwegian Jaerhon (google the breed some pages show the difference in the down color of day-old chicks from the two varieties).
R.C Punnet also provides some clues on the down color in his publication in the Journal of Genetic titled "The Legbar". He said that when developing the Breed he started with Brown Leghorn Pullets from the UK and a Barred Plymouth Rock from Canada. The 2nd year he imported Brown Leghorns from Holland. The UK leghorns are know to be lighter than Continental leghorns and Punnet said that he noticed that the Dutch Leghorns all had a darker down color than the British Leghorns. In crosses he proved that the dark down color is dominant and the light down color recessive. So the blond chicks from the yellow banded Green Fire line make have a recessive down color that has resurfaced or been reintroduced for out crops to UK Leghorns (not 100% sure if Punnett was seeing the blond chicks or something in between the blond and the dark)
Note: My blond color cockerel feathered out the same as my dark down cockerels.
Finally, there are "white" Legbars that have yellow down. These are NOT standard colored Legbars, but rather have a recessive gene that inhibits any color form entering the plumage of the bird. These Legbars grow out to be all white and should not be breed unless you are working on a novelty White Legbar flock..