Regarding the "monkey" line, has there ever been any other dialogue in a Star Fox game that refers to someone as an animal or with an animal trait?
Star Fox 64
Falco: "Time to show the monkey who's boss!" (in Japanese this is "Let's show the monkeys the difference between them and us!")
Slippy: "I'm monkey food if I don't leave!" (only worded this way in English)
Andrew: "Stick to the pond, Froggie!"
Andrew: "Did you think an inferior animal like you could meet Master Andross!" (only said in Japanese; English line is "We'll make sure you'll never reach Andross!")
Star Fox Assault (a lot of these might only be worded this way in the English version, I don't have the Japanese lines convenient for me to check)
Fox: "ROB! Find the blackhearted ape's location!"
Fox: "All right! This time we take that ape down!"
Fox "Oikonny, you ignorant ape, what are you up to?!"
Falco: "Where did that crazed chimp, Oikonny, go?!?"
Falco: "You haven't changed a bit, frog boy."
Falco: "This is ridiculous! Fox! Take care of that stupid frog, will you?"
Falco: "You dirty swine!"
Falco: "You swine! But you're supposed to be dead!"
Falco: "Shut your trap, lizard, or you and I are gonna scrap!"
Falco: "Great, it's the lizard boy, Leon."
Falco: "Not bad for a fox,"
Krystal: "It's OK. The general's a tough old hound dog."
Wolf: "Quit your croaking, toady."
Wolf: "When I'm finished with you, I'm gonna have a foxtail for my spaceship!"
Wolf: "You stupid dog! Get a hold of yourself!"
Leon: "Well looks like I'm better than the bird..."
Leon: "Are you all beak and no bite, birdbrain?"
Panther: "Quiet, bird."
Andrew: "No quarter! Show these dogs we mean business!"
Cornerian soldier: "Stinking Ape! We underestimated the strength of his reserves..."
monkey criminal: "Let's skin this fox and his whole crew"
monkey criminal: "We got the fox cornered!"
monkey criminal: "Let's skin this fox already!"
Star Fox Command (the English script deviates a lot from Japanese, so a lot of these might only be in English)
Fox: "That lousy ape is nothing more than a crazed maniac!"
Falco: "What's up, froggy? I just got here."
Falco: "That dang frog! I bet he's dippin' his webbed toes in a nice pool somewhere!"
Falco: "Don't pretend, frog. You just want to go see your new squeeze!"
Falco: "Not bad. Maybe you weren't dropped on your head as a pup after all."
Wolf: "I hate that frog..."
Wolf: "That birdbrain turned and ran, eh? Or maybe he screwed up and became Anglarian fried chicken!"
Wolf: "Tweet tweet tweet! Is that all you got, little birdy?"
Pigma: "Box? You arrogant... hrrfff...bird..."
Pigma: "...Talk...talk...enough talk... Now you die... little birdy..."
Anglar Emperor: "Your little band did well to track us this far. Perhaps the dog can smell a scent other then his own fear."
enemy: "Those frogs look delicious! Yum yum!"
Just going off number of lines, Falco is definitively the most racist character in Star Fox.