I know I might sound like a jackass, but is it really that hard? All I did was throw a Valkyrie at spot H, then Katie at G, Prince at B, and then Spica and Bashira at X and Y, put a healer at P, wait for Katie's skill to be ready, then put another healer at Q. Granted, the Valk I used was Clissa, but a decent enough Valk or any other cheap enough yet decently strong duelist should do. I think.