Himbos are defined as attractive, unintelligent men, so the topic I'm focusing on is intelligence. I think one defining mark of intelligence is applying what you know in furtherance to one's goals, and not just in knowing things.
Kronk is someone that knows a great deal (cooking, speaking to squirrels, logistics to cut off Kuzco's path, etc), but he allows himself to be manipulated by Yzma. He can adapt to being a line cook very quickly but at the same time forget his mission of capturing Kuzco. Though he is knowledgeable and skilled, he lacks the skills for introspection to direct the life he wants to live. To be fair, Yzma hinders his development a lot by doing his thinking for him and not being constructive in her criticism (to put it mildly).
So could a himbo be knowledgeable in math/quantum physics, etc? Yes.
Does that make a himbo intelligent? No. They haven't developed the habits for success and are usually not situationally aware, but they have the potential to be intelligent. I think one way to make a himbo compelling is to keep them on that border.
