Apparently the main villain of the area will be Tiki Tong from Donkey Kong Country Returns.

https://www.ign.com/articles/first-details-of-donkey-kong-country-theme-park-at-super-nintendo-world-announced

I'm going to say that something like a food item being named after him doesn't count, he needs to appear visually.

Must appear within the first three days of post-preview opening.

The important thing to remember is that K. Rool wasn't invented by a Japanese studio. So it is commonly believed that there is little affinity for the character in Japan. That's probably part of why he's not the main villain. He's also creepy looking in a way that Bowser is not.