Reddit reviews Primates: The Fearless Science of Jane Goodall, Dian Fossey, and Biruté Galdikas

A couple ape examples off the top of my head: the librarian orangutan in The Color of Magic and the various chimeras in Daughter of Smoke and Bone. And Planet of the Apes, of course.

If you're going to use nonhumans, I would much rather see them acting like nonhumans. If you want a quick read to pick up some ape behaviors, check out the graphic novel Primates (science, not fantasy).

"He was a baboon" totally makes sense, but you could also twist it so that characters were calling him that when he's another species and they're just calling attention to whatever stereotypical traits they think baboons have.