I wouldn't use any of the F1 cockerels. I'd breed the F1 pullets back to the Black Silver-laced males. Preferably, one unrelated to their father if you have it.
Yes. If you okay with the genetic calculator it’ll be the same. In a funk tonight (had to put my almost 15 year old dog to sleep) or I’d explain more and show pics of Laced to non-laced birds, but you can see some of the in the Fairy Tail Farms thread of mine on here.
Orpington lacing is actually different that Wyandottes. Their tails are laced, while Wyandottes are not. So it’s actually the same genotype that Sebrights have.