That's what I would have Called it. It would signal a new day was about to be made- as the Evil of the prior day was destroyed. Change it however you wish if you'd like- It's simple, and gets the point across.
Look's like I am gonna be in for a beating... SO... AWESOME! GO TWILIGHT! Are you ready Twilight Sparkle? All the way to the end, Princess Celestia! Why don't I get awesome lines to say?!?! Hmm... CRUSH. KILL. DESTROY. SWAG. CRUSH. KILL. DESTORY. SWAG. CRUSH. KILL. DESTROY. SWAG! Y U NO LEAVE US ALONE!?!?
"What would've happened if the Elements of Harmony failed?" Answer: the power of love prevails. Twilesta is no exception. BTW IMO you predicted what would happen in the event that the element's of harmony could not be used. And as always, love your art bro.