I got my first Cream Legbars from the 2011 flock of Green Fire Farms Direct 2010 imports from Europe. I too was surprised at how much diversity their was in the group. I got three pullets that were from the 2011 A-line flock meaning they all had the same father and were from any of the five imported hens in that group. None of the three looked like sisters though. The cockerels I worked with were even more diverse. One cockerel was from the B-line flock meaning that they he was a grand son of the A-line flock (or cousin to the three pullets) and another cockerel was from the C-line flock meaning he was from the the second European import that can the middle of 2011 and was unrelated to the other birds.
Here are chick photos of some of the chicks from the 2011 flock. Notice how light the cockerel is on the far right and how dark the cockerel is on the far left.
View attachment 1224854 Here the pullet on the far left is a little lighter than the one second from the left.
View attachment 1224865 Here are twp more cockerels that we got in 2012. Again note the really dark cockerel on the left and the lighter cockerel on the right.
View attachment 1224857
So...as others have indicated there is a lot can be a lot of variation. The creator of the breed breed English Brown Leghorns to an Imported Barred Plymouth Rock from Canada in the first year. The offspring from the English Brown Leghorns had a lighter down color. In the 2nd year of the breed creation import Dutch Brown Leghorns where breed to the first generation crosses. The Dutch line had a darker down pattern. A full study was done on the down patters and published in the Journal of Genetics in 1948. The study included several hundred chicks and over multiple years proved that the lighter down patter of the English Leghorns was recessive to the darker pattern of the Dutch Leghorns. Both are in the Legbar Genome today. They are both forms of the Wild Type Primary Color Pattern but but produce the wild type pattern from distinct e-loci genes. I found in my own studies that the dark type have more vibrant reds in the adult plumage but other than that you can not tell the difference from one type of the other in the adult plumage. The dark type pullets have clearer autosexing down markings, but the light type cockerels show great contrast from the pullets so one is just as good as the other and since both types have survived for 60+ years they are both likely to survive for another 60+ years in the genome.