If you crossed a 'lemon cuckoo' orpington rooster to buff ameraucana hens, all the offspring should be buff barred with beard/muff and a pea comb. Eggs would be more green than anything, and thanks to the sexlinked barring, they would have white legs, not slate. Just select the best colored/patterned offspring from that and either mate them together again or back to other buff ameraucanas. Just keep in mind that if you take one of the 'lemon cuckoo' hens and mate it to a buff rooster, you'll end up with the basic sexlinks (buff pullets and buff barred cockerels that would be impure for barring)
Just an FYI on why I put ' ' around 'lemon cuckoo' is because as someone that loves genetics, I hate that they call it lemon cuckoo when there is nothing lemon about it. Lemon makes many people think of citroen which is a diluter...