White leghorns are genetically "dominant white", so the chicks will be almost all white, with a few colored feathers. Those colored feathers will likely be barred, but not as light as the feathers on your roo. The eggs might be tinted brown, but could be very white as the leghorns also have a lot of shell color inhibiting genes.
I'm pretty sure they will be great layers, and most characteristics will be between their parent's traits.
I'm pretty sure they will be great layers, and most characteristics will be between their parent's traits.