Stereotype characters can be used as a lens to examine the greater human whole. With non-human characters this is always the case as they must be less than the greater human whole, or they just become human. Often non-human characters strive to become more human, like Data in Star Trek: The Next Generation.
I was using tropes in a general sense to point out that non-human characters must always be limited by some sort of trope so they can be pointed to as something other than a human that looks different.
What you seem to be missing is that this is not just a trait involving non-humans. And that the phrase "less than the greater human whole" is a bit of nonsense.
This is edging into dangerous territory, but if I were to read Robinson Crusoe most of the natives of the island would be limited by a trope, because they are being pointed at as something different. You could say the same thing about any "category" of people. Read the Legend of Sleepy Hollow, Ichabod Crane is strange, he has long limbs and odd interests. Watch Beauty and the Beast. Belle is a strange girl, she likes reading and wants to go on adventures.
Sometimes, like with Belle, it is a drive by trope. Mentioned then gone and never brought up again, other times like with Ichabod, it is much more defining of the character.
Whether human or not, if an author wants to say "hey, they are different" they usually give them a trope to define them. And I'm not sure I'd use the term "limit" which gets into the second issue here.
What do you mean by "less than the greater human whole"? The only thing I can think of is that you are trying to say that this person has a defined set of traits that is only a subset of all possible traits.
The immediate issue though is that no one, not an individual nor a group of humans, presents the "greater human whole"
Quakers were pacifists. The Janissaries were very much not pacifists. So, if I were to right a story about Quakers, and the fact that they were pacifists, I would by your definition, make these human beings "less than the greater human whole"
And you might say, "But they are human, they could choose not to be pacifists" and you would be right, but then they wouldn't be Quakers, and there are reported tales of Quakers choosing to stand by and do nothing while they were being killed, because they believed so strongly in pacifism.
So, in a way, you are right, non-humans only take a subset of human traits and exemplify those. But we don't talk about anybody as embodying every single possible aspect of humanity. To write about a man is to take a subset of humanity, because women are not men, and they have different traits. To write about a man who is a police officer is to take an even smaller number of traits, because most of humanity are not officers of the law, and being an officer of the law implies certain things. Writing about a man who is a police officer in Tokyo is making an even smaller subset, because police in Tokyo are different than police in the states or in Iraq or in North Korea.
To define a character at all, is to make them "less than the greater human whole" so presenting that as a problem with writing non-human characters is nonsensical. Sure, maybe there is not a single Klingon who is not honorable. There is also not a single Math professor who can't do Algebra. Defining a group, by its very nature, limits them from all possibilities to some smaller set of possibilities.