@Amer can probably explain that better than me. But a Blue Wheaton bird crossed to a black bird would result in Blue and Black offspring with leakage (I'd imagine). The second cross would depend on the color the female is and how that would interact with the Wheaton coloration. Blue is a...
Breeding a Blue Wheaton cockerel over (Black) Wheaton females would result in both Blue and Black Wheaton. If you bred him to his Blue Wheaton daughters you could get Splash Wheaton.