The Rescuers (Disney film)/WMG

The voice (Shelby Flint) singing the somber songs in this movie, is either Penny's singing voice, or what her singing voice will sound like when she gets older.

 * Jackie Evancho proves that even little girls can have singing voices beyond their years...
 * Either that or it's merely being sung by a Penny-esque perspective...

Cody from The Rescuers Down Under is Cody Martin

 * I mean think about it! They're both blond, sorta timid and obviously American. I think that he was taken by his dad to Australia because that's the only place where he could get a gig. Cody wanders away, gets found by the poacher and goes on the adventure. His parents, finding out what had happened, takes him back to America. And Cody, obviously scarred by the adventure, never ever wants to think about it again.
 * I wouldn't call Cody timid.

Cody's father was a ranger.
Even for a young, impressionable, naive kid who has the whole Australian outback as his playground, Cody seems very attached to and concerned about the animals, and he is constantly throwing the threat of the rangers in MacLeach's face; this suggests at the very least that Cody has either been taught by his mother or teachers a great respect for rangers, or he's seen them in action. If his father was a ranger, though, this would explain Cody's feelings and loyalty in a more personal manner, particularly if his father was killed by one of the poachers he was hunting down. (No, not necessarily MacLeach, who might have recognized Cody or who might have recognized him, though it could have been.) This could also explain the mysterious ability Cody has to talk to animals (assuming it isn't some special talent only children have), if it's a talent rangers have and Cody inherited it.