How did Sanae turn from Born Unlucky into a Born Lucky? The real Sanae's power is to create miracles, with particularly large ones taking long time to reform. So she isn't as much lucky as she is using her powers over miracles to pull off impressive stuff like clutch revenges, but it took so long to get it going.
Cirno, and every other fairy in Touhou, has Resurrective Immortality, allowing them to come back from dead as long as they have the proper motivation. So when the Mob accidentally released Cirno but she came back, it was because not even the PC cannot kill something what cannot be Killed Off for Real.
