It doesn't matter if it is a tooster or hen, if the bird has two copies of the blue egg gene, it will give one copy to each chick. Pure Crested Cream Legbars are supposed to have two copies of the blue egg gene (not saying whether every one actually does, just that they are "supposed to.")
A...
White legbars, yes. That would be the recessive white gene.
But not white-and-brown chicks, like what OP showed. Those chicks must have the Dominant White gene, and it is impossible for a Cream Legbar to carry Dominant White without showing it.
Legbars are supposed to be a pure breed, that...
I think the white barring would be visible in at least some places, but I'm not entirely positive. To some extent, it will depend on where the Dominant White actually is.
I've also seen photos of some chickens that have white barring on white feathers, and it is a little bit visible if you look...
Green eggs, probably not dark enough to be considered "olive."
The crest gene is dominant.
They should, but the crests on the mixes might be smaller than the crests on the purebreds.
Other than white barring, there should not be anything in Cream Legbars or Rhode Island Reds to cause white...