Here is how Princess Yuna, Portal Glow, Dipper and Mabel Pines, Lightning McQueen, Mater, Cruz Ramirez, and Dusty Crophopper were found in Fantasyland Rescue.
As for Yuna, she was getting too tired out after releasing the beam.
Princess Yuna: (panting)
Lightning McQueen: Take it easy, Yuna, you're overusing your magic.
Princess Yuna: (panting) But I have to be sure anyone can find us, Lightning.
Spike (Human): I guess, we're waiting for anyone.
Portal Glow: I guess so.
John Smith: Princess Yuna? Portal Glow? Dipper? Mabel? Lightning? Mater? Cruz? Dusty? Anyone in here?
Princess Yuna: Yes, it's us!
With that voice recognized, Vice Principal Luna knew that voice anywhere.
Vice Principal Luna: John Smith?
John Smith: Vice Principal Luna?
Dipper Pines: Did they know each other?
Mater: What in tarnation is going on here?!
As Luna walked up to John, she was amazed to see him again after a long time.
Vice Principal Luna: I thought I'd never see you again!
John Smith: I always dreamed endlessly about you, Luna.
Meanwhile at Canterlot, Airazor flew to the throne room to inform Celestia and Luna.
Airazor: Princess Celestia! Princess Luna!
Princess Celestia: What is it, Airazor?
Airazor: John Smith has found Yuna, Portal Glow, Dipper, Mabel, Lightning, Mater, Cruz, and Dusty!
Princess Luna: Oh, thank goodness! Are they alright?
Airazor: They're fine, they somehow found a tunnel that leads to Equestria.
Hiro: That tunnel was never used for many decades, Yuna must've found that way this quickly.
Princess Luna: Take us to them, Airazor, my sister will spread the word of their whereabouts.
So, Airazor led Celestia, Luna, and Hiro as they spread the word for great news.