User blog comment:FairyRaven/Fairy Tail Chapter 363: The Stories That Demons Read, Review and Commentary/@comment-70.233.138.240-20131206142453/@comment-7418318-20131207095133

Yes, but this time it was specifically said that the lives are the keys.

To give the exact quotes:
 * Mangastream: "The lives of those three are the keys to that seal..."
 * Mangapanda: "The lives of 3 people are the key to removing the seal..."

With Wendy being the one to say that, it's still possible that she's mistaken, but with the way the current and former council members were killed left and right so far, I doubt it.