Wonder if there's some kind of prophecy that made them think it has to be Waffles.
Nope .. Im sure is something more obnoxious than that.... Politics
The minister and the kidnapper are used to deal with humans in a respectful manner, as they address them as "Humans" not as "Non-Furs" (slur in Animalia) possibly they already had conversations with some people within high ranks in the human side to begin a pact of equality, and they need someone strong but at the same time refined, polite and enough educated so he doesn't behave as a barbarian/brute to appeal the human side, so they can show that they are strong but not unreasonable (very difficult to achieve in a civilization whose culture is "Strength is Everything and Warrior's Pride") and there isn't a better candidate that the Hero, Waffles fill all those requirements.
Notice the minister's change of opinion regarding Doben when he stopped his attack and regrets not having known it sooner, this due possibly all the political arrangements already are done under the name of Waffles, if they know early that Doben can be reasonable then they would have put him in as their representative.
Another big hint is when the minister says "A Hero who's just strong isn't good enough" and while everyone including me dislike him for kidnapping Doben's Sister, we all know that his words are 100% true.