To all the people who voted that N's not a Zoroark, what busted the theory?
Nothing is required to "bust" the theory. The burden of proof is on the person making the claim.
And the topic on Zoroark brought up some good points. The strongest points I've seen are:
N: "And Zekrom/Reshiram...thanks for everything. My journey with you has been truly wonderful! From now on, I want you to use your power to help this Trainer realize his/her dreams. I know. I'll miss you, too... But your task is to help humans who seek ideals/truth. I learned so much from you. I'll do my best to tell everyone else what I learned on my own. I'll be OK! I can talk to Pokémon! I'll become the bridge between Pokémon and Humans! That's my ideal/truth!"
In Black 2/White 2, N leaves his dragon because he believes that the Dragon's duty is to help "humans that seek ideals/truth." After that, he talks about how he's seeking an ideal/truth. Since he's still seeking his ideal/truth, wouldn't that mean that he's leaving the Dragon because he's not a human?
In general, Memory Links are told in the perspective of the person you talk to. One Memory Link has you talk to a Zoroark, and then the flashback is shown in N's perspective. The logical conclusion is that that Zoroark is N.
I really don't like this theory. As you said, Cyndaquil is not a rat (or a mouse, or anything else resembling one), and Fennekin is not a dog (though that's sort of semantics). I can still go with Charmander being a dragon, considering Charizard.
It's kind of disappointing, because I'd really like to see a fire rabbit starter, but that fits with this theory.
Umm... cyndaquil is a mouse. http://www.serebii.net/pokedex-bw/155.shtml "Classification Fire Mouse Pokémon "