With ONE specific white bird you can cross to another colour. If you hatch enough chicks you can begin to make predictions for the genes THAT white carries, but it will not be the same as a different white.
Looks like a blue or splash, although it certainly could be lavender. I see the white crests in polish and polish crosses, and I remember seeing wcb silkie chicks a few years ago that matured into regular blacks.
Very cute chicks!