THE QUEST OF THE CANDIDATES

A hero is a character who is admired for his/her courage, outstanding achievements or noble qualities. A hero in fiction normally has a long and arduous search for something; the quest.

Do any of the candidates show noble qualities of high moral standards?
Do any of the candidates show courage, summoning personal strength in the face of pain, grief or frightening circumstances?
Do any of the candidates show island achievements, a thing done successfully, usually with effort, courage or skill?

With all the episodes, events, missions, and tangents that the candidates have been involved in, it is hard to identify a single noble quest.

Jack's original real world quest was to find his father and return his body home. He failed.
Sawyer's original real world quest was to find the con man who drove his father to murder and seek revenge. He did so by strangling Cooper. But was that a noble act?
Kate's sole mission in life was to run away from her problems or responsibilities. She has not been able to settle down or face the music concerning her past.
Hurley really had no mission or direction in his life. His non-existence was changed by winning the lottery, which he learned was a curse. His return to the island was not noble, but more like guilt and peer pressure. Since returning to the island, he has become a speaking pawn for Jacob.
Jin's mission in life was to be successful, to get away from his poverty. He found himself as his father-in-law's lapdog in an unhappy marriage. Since, his goal was to reunited with Sun, but he has not been able to do so.
Locke's original real world quest was his personal acceptance by anyone (his father, Helen, his boss). But once he was "cured" on the island, he never achieved any of his new goals. He never was a good leader. He did sacrifice himself in the FDW to reset the island time skips, as in the end he was murdered by Ben and returned to become the new form of Flocke, who has killed many people.

What is the great, noble cause the candidates are supposed to embody and fulfill?
We don't know. The mere message of stopping Flocke seems like a hollow instruction without meaning.