I mean, technically we’re all animal and all human (homo sapiens sapiens is just a particular species of human which is part of the Animal Kingdom)... this question really smacks of humanism and human (specifically Homo sapiens sapiens) exceptionalism. To create a cutoff line between “human” and “animal” would be a false distinction because, in short, there is none.
But to get to the point, if more than one species were to survive and effectively compete, that would be interesting. If it was difficult for Homo sapiens sapiens to communicate with and coexist with each other IOTL, and a difference in skin tone and a slight difference in facial features was enough to generate massive discrimination, atrocities, and conflict, then who knows what different species will attempt to do to each other? Means of communication for each may be fundamentally different, as well as cultures, tastes, living conditions, advantages/disadvantages (maybe neanderthalensis is stronger and cold resistant while sapiens is more agile and heat resistant). They won’t just begin with slight differences that can be merged and forged into larger cultures, communities, and civilizations; it is likely that social and biological differences will present a real challenge. I wonder what the outlook of such humans would be. Now that our cousins are all dead, we can safely declare our superiority as the only sapient species on the planet. Imagine living on a planet where there are whole groups, communities, and nations that are just as advanced, powerful, and intelligent as your own, or close enough to truly challenge you, but that cannot make children with you, cannot effectively convey certain ideas to you or vice versa, that could, due to brain structure, have a vastly different fundamental conception of the world as compared to you, vastly fundamentally different cultures, ideas, and societies as compared to yours. I can’t describe how different it would be compared to our world, but think of it like this: every book you’ve read, every song you’ve listened to, every work of art you’ve admired—they’re all from minds that are built in almost the exact same framework as yours. Even minor differences can cause such extreme things as genius or psychopathy. A malfunction in one gene, FOXP2, and its protein means you can’t speak. One gene. People of all cultures and ethnicities have essentially the same brain structures, the same methods of speaking, the same emotions and emotional/mental needs, and many of the same critical genes that define personality, behavior, and communication. If there were to be a group of minds that were, as a rule and not an exception, even slightly different in these regards, it would be amazing and terrifying. Art, literature, and culture would be unrecognizable, for starters. Cuisine and sports too.
Oops. I missed the point. Umm, well, in that universe, I guess all Homo sapiens (not just Homo sapiens sapiens but their cousins too) could be considered at a similar enough level in... well... everything to be “human”. However, it would be factually incorrect to say that, say, Homo erectus is not human. Anything under “homo” is by definition human. And all humans are a part of the animal kingdom.