That "latinx" thing is adapted from a way of "gender-neutral spelling" popular among Spanish speaking leftists, using an "x" in place of a vowel when the vowel would determine the gender of the word (as you say, not just in pronouns). It's not new at all though, that way of spelling has been around in Spain for more than a decade. Nowadays it's more common among Spanish leftoids to change the vowel for an "e" instead ("¿Nosotres somos latines o blanques?"), because that way it can be pronounced. It's equally irritating and amusing.
(Edit: just saw I'm late with this, but this wasn't brought by colleges and academia, at least not in Spain. It was brought by leftist political parties and organizations)