I would not jump to that buff being a roo, either. My one bo developed a tad bigger comb and waddles, and is clearly a hen, now at 20 weeks.
I do agree, though that if those are orps, they have the wrong comb.
yes it looks like a comb of a wyandotte though on your BO? Mine has the real BO comb I think you may be wrong on the breed of her. They really do make them in buffs for your wyandottes.