I would think in reference to the character they would use the 3 syllable pronunciation but who knows!
I did fall into a rabbit hole sometime ago trying to answer the question "how is it
supposed to be pronounced?" but the answer was that there isn't one.
I found a map of the US and saw it's pretty split with most Americans using 3 syllables. All along the coasts and through the East and most of the midwest was 3. Central US 2. Texas and surrounding states a mixed bag. I started to wonder how English-speaking Europeans would pronounce it until I remembered there are no coyotes in
Europe (though they do have jackals).
Seems like it's original etymology was from Nahuatl coyotl, pronounced most similar to the 2 syllable pronunciation of the word, but it was then adapted into Mexican Spanish sounding something along the lines of kai-oh-teh.
But yes, I hate the slang. :(