McLeach has a Southern American accent despite the film being in Australia. He's likely on the run from the law for his poaching, so he's hiding out in Australia. Australia may be his most recent hiding place.
Joanna seems like a weirdly specific name for a lizard, particularly for viewers who aren't from Australia and can't differentiate species. However, it all makes sense when you realize she's a goanna lizard, which rhymes with Joanna.
Cody leaves the room with the trapped, sentient, talking animals, with McLeach telling him he won't ever see them again. We never see anything that contradicts the apparent implication that he slaughtered them all. It did seem like McLeach immediately tricked Cody into leading him to Marahute, then tried to kill him, leading directly to McLeach's own death. All of this seems to happen in sequence, with no time to go back and kill and skin the animals for sale. Then again, it raises the question of what happened to the imprisoned animals. All the characters seemed to forget them, meaning they all slowly starved and dehydrated to death unless Cody somehow found the hideout again or brought rangers. Or worse, if Joanna, who appears to be a Lace Goanna (Varanus varius), remembered they were all there and went back, the rest of the animals might have had to watch the carrion eater eat them one by one as they died.
Joanna is seen to be afraid of McLeach — which leaves open the question of whether she was always that mean.
Think about how the whole crocodile falls scene in the climax must have looked like from Cody's (an eight year old!) point of view.
Speaking of the crocodile falls, when McLeach shines a light on them, they immediately go into the water, almost like it's a signal that they associate with something edible going to be given to them. He even yells, "That's right, babies! Suppertime!" Likely, this isn't the first time he's fed someone to crocodiles.
The death of Marahute's mate gains a new depressing layer when you remember that eagles are monogamous. She loved him and only him and would have been with him for her whole life...but she didn't get the chance because McLeach killed him.
Fridge Heartwarming
Wilbur is (grudgingly) tasked with watching Marahute's eggs while Bernard goes to rescue her, Bianca, Jake, and Cody and they hatch by the end. It was sadly confirmed earlier that McLeach had killed Marahute's mate, but with Wilbur being present at their birth and consideration of imprinting, maybe the chicks will grow up with a father figure after all.
