We don't know the scientific name of what the mogwai mutate into. Billy gives them the name "gremlins" after hearing Mr. Futterman's story about the mischievous creatures that brought down planes during World War II.
"Mogwai" is allegedly a Chinese word meaning "evil spirit" or "demon." It's an appropriate name for these creatures, which harbor something very dangerous beneath their cuddly exterior. But if the filmmakers called their movie Mogwai, no one would know that that was.