Can't be Orpington/Ameraucana...as the OP's birds have rose combs.
Orpington have single combs, Ameraucana (true not just EE) have pea combs.
To express single comb, both rose and pea have to be absent.
To express pea, rose has to be absent.
So it would be impossible to get a rose comb from an Orpington/Ameraucana cross.
It could be Orpington/Wyandotte as the Wyandotte rose would be dominant over the Orpington single. Depending upon the full genetics of the rose comb, you could get rose comb and single comb birds.
However, that doesn't solve for the grey legs....but leg color is tricky. I've had a yellow leg Barnevelder over yellow leg Cal Grey produce black/grey leg mixes. I have seen grey legs follow blue coloring.
So the blue/lavender could be bringing the grey legs, but I'll let someone else with better leg genetics step in on that.
LofMc