Rousseau Was Right is in full effect in this movie, Humanity as a whole, when they find out what the latest popular band was, they cheer them on for their journey home, and if memory serves me right, they actually help as well. Seeing one species help another back home is enough for this troper. The only exception was the villain, who was... well evil.
Humanity quickly got over the truth that their are aliens and many popular musicians being aliens. News reporters quickly show the public the aliens and their troubles, police comb over the evil villain's lair, scientists work to restore the aliens memories, and politicians work to organize sending the aliens back to their home in Shep's spaceship.
The Crescendolls are definitely True Companions. Some examples throughout the movie include:
After Shep is able to save the guys, they all immediately work together to save Stella.
When the gang arrives at the Earl's castle, Octave helps Baryl from slipping on the way up.
When the Earl shoves Stella into his strange machine, the guys are visibly horrified and immediately start fighting back.
After Octave wakes up in the hospital, the others are right there by his side.
A quick moment: When the Crescendolls fight back against the Earl and his minions, the Earl ends up falling over the edge of a cliff. However, as he's falling, Arpegius actually grabs the Earl's cloak and tries to pull him back up. Even after everything the Earl did to them and countless others, the Crescendolls still tried to save him.
The implied All Just a Dream ending. It's kind of sweet to see the boy's mom putting him to bed.