[Jewbacca]

Yes corn is fine.

There is a ton written about mules, actually. If it happens by accident, what to do, etc. May or may not be OK, depending on if you consider a horse and donkey the same “kind”. Opinions differ.

As with a bunch of other close questions (e.g. fruit trees, dogs and wolves, etc). Things that breed naturally give rise to reasoned disagreement.

But an alligator and catfish? Nope.

And the “because I said so” makes perfect sense now in the age of DNA splicing. Some horrid monsters will one day arise from this.

[null and void]

How about derivatives? Would milk or meat from a beefalo be OK? My sense is no, fruit of a poisoned tree, or unevenly yoked plowmates.

How about an antibiotic or vaccine developed using humice, mice with human immune systems? Dicey. Although nothing from the animal is in the final product, and the human immune system is used to add an immune system to an immunodeficient mouse without cross breeding the species, per se it's the animal equivalent of flax and cotton fabric.