Don’t know about the demonic references, but the intentional creation of chimeras (a mix of two or more species of anything, plant or animal) is forbidden to Jewish people by Leviticus 19:19.
https://www.jewishvirtuallibrary.org/mixed-species
I believe there is a similar prohibition against cross-breeding to all people (Jewish and Gentile) in the portion of the Torah that has general application to all people (the Noahadic laws). Something along the lines of “don’t crossbreed your cattle”. I’m focused on my own contract. I’ll leave that in your able hands.
Cross breeding, as in making hybrids, produce sterile offspring as a rule and I can see why God forbade it.
However, it seems the intent of not intermarrying with Gentiles was more because of the danger of spiritual corruption, that would be following after their gods, like Baal, Molech, and Ashtoreth, which happened almost every time the Jews got involved with pagan (Gentile) nations.
Mankind has this propensity for evil that is in our very make up and going towards evil and self-destruction is easy, but staying pure and true to God, just like doing anything good for you, takes work and is hard and requires perseverance and discipline. Look how hard it is to simply eat right, sleep well, and get enough exercise. Being a TV addicted couch potato, chowing down on junk food is much easier and honestly, to a degree, enjoyable.