He might be a mix, but I am pretty sure he is not a pure Cream Legbar. For one thing, his legs are the wrong color (should be yellow.) Various other points don't look quite right either.
I am also not sure he has the blue gene, although I have a hard time telling dark blue from black in chicken feathers.
I would expect a bunch of blue chicks with white barring, and maybe some splash chicks (also with white barring.) You might also get some chicks with no white barring, in which case they would just be blue or splash. All chicks have a chance of having red or gold leakage as they grow up, especially in the shoulders of males and the breasts & hackles of females.
For egg color, if the rooster has the gene for blue eggs, you will get daughters that lay green eggs (blue with a coating of brown on the outside.) With Marans mothers, the pullets are likely to lay dark green eggs, sometimes called "olive."
If the rooster does not have the gene for blue eggs, then his daughters are likely to lay brown eggs, possibly dark brown, but probably not as dark as the eggs their mothers lay.
It is possible for a chicken to have one gene for blue eggs, and one gene for not-blue eggs. If the rooster has that, half of his daughters will lay green (they get the gene for blue eggs) and the other half of his daughters will lay brown (they get the gene for not-blue eggs.)
Because a rooster does not lay eggs, you won't really know what genes he has for egg color (unless you know quite a bit about his parents, or if you work out his genes based on what egg colors his daughters lay.)
