Also worth noting something which I'm not sure if it's been mentioned in this thread (too much to read lol):

Originally Emet didn't have the "you're not actually alive so genocide isn't actually evil" excuse, he straight up just wanted to kill everyone born after the summoning of Zodiark to bring back the people who sacrificed themselves to stop the end of the world... so he was definitely willing to kill more than 'mere reflections' just to bring back his old friends.