Obviously the story about Haitians is fake and racist. The real story is that an American woman did get arrested for torturing, killing, and eating a cat in front of other people in Canton, Ohio, which is about 170 miles (~275 km) from Springfield.
Politifact: Arrest of a Canton, Ohio, woman unrelated to baseless claims about Haitian immigrants in Springfield one comment down.

However, my preferred theory is that JD Vance heard that liberals eat pussy, and the random hateful sentiment generator in his head came up with migrants eating cats.