To beat Kanako, you need to use Youmu's last word spell card. This guarantees 100% hit death status on Kanako. Alternatively, you can use sakuya with full power points in murder/2H swords with IND raising equipment/buffs and open with private square/full moon revenge and repeat as necessary until Kanako gets one-shot. while each of Sakuya's hits is a lot less than 100% kill chance, this method will most likely kill Kanako faster than if you wait around for Youmu to get her last word
You can use Byakuren spell "漆黒の病魔" on Suwako for stone status too. Satori's Stone breath also works. Using status inflicting methods with weapons require high IND. (inflict chance with weapons is usually low, this is not a recommended method).