That looks quite a bit like some of the chicks in this thread, that are a cross of Buff Orpington and Barred Rock:
https://www.backyardchickens.com/threads/buff-orpington-plymouth-rock-cross.319500/
Barred Rocks are genetically "black" chickens, just like your rooster, so crossing with a Buff...
Interesting bird!
Do you remember what color it was when it hatched?
I'm guessing it came from the black-split-to-Lavender father, and a Buff mother. I see that predicted "black with large amounts of gold or silver leakage" from that cross, but I certainly was not expecting THAT much gold/buff...
With the White Leghorn rooster: expect white chicks, with some flecks of black or maybe flecks of blue, from any hen.
With the White Leghorn hens, I would also expect white chicks, with some flecks of black, from your Orpington rooster. If they mated with the White Leghorn rooster, then of...