I must start with the pedantic point that
Homo sapiens is a species and anything of the form
Homo sapiens whatever is a
subspecies. There is some debate over whether Neanderthals and Denisovians are separate species or only separate subspecies from us. And I think therein is the answer to the original question - even though I don't think the taxonomy itself will enter into it. (Religions, and to a lesser extent legal systems, would not tend to ask the scientists "Is this
Homo sapiens, Homo somethingelse, etc.?" and base their opinions solely on that.)
If these newly discovered hominids fall within the broad accepted parameters of humanity - they may, on average, be very hairy and not very bright, but there are plenty of hairy stupid people about - then I don't think there would be any question they would, for the most part, be accepted as people. They would likely be classified as a subspecies of
H. sapiens, and parallel to that - not because of it - most organized religions and legal systems would find no reason to deny their humanity. (It's been said that Neanderthals could easily pass for modern man in everyday settings.)
It would only start to be a problem for some if there was some significant deviation from modern man. What if they had some unusual anatomy of the foot, for example, making them more like chimp feet? What if there was a distinct secondary sexual characteristic, like the facial flanges that form on dominant male orangutans? Even then, unless the population was large and very distinct, I think they would be accepted as people. Forteans know there have been towns and islands where the inhabitants tend to have "crablike" hands, or polydactyly, or a tendency to walk quadrupedally, etc., but this has not caused us to consider these people anything other than people. At this point, though, some religious groups (especially those without a strong hierarchical structure) and some conservative legal systems might start to see them as Satan's spawn, degenerate mutants/half-breeds, or the like.
It only gets interesting when we go way off the human scale. Consider something that looks like Australopithecus - or if you prefer, Gigantopithecus. They make tools like spears with reasonable skill. They have a simple spoken language and the very rudiments of a written one. They can count on their fingers, but not much higher. They exhibit some religious beliefs and rituals. What of them?
I think organized Christianity - Roman Catholic, Anglican/Episcopalian, etc. would accept them first as God's creatures and possibly second as people if they could convert a few of them. Probably the same with the more liberal divisions of Islam. Victory has said traditional Judaism would accept them as surprising survivors of the Flood, and I have no reason to question his expertise on this. Most Eastern religions would likely accept them for what they are, rather than try to shoehorn them into "human" or "non-human". But there would be an uncomfortable number of religious people worldwide who would view these new people as evil, or as something no better than pets - i.e. slaves.
Modern legal systems would probably be troubled. I think they would try something akin to the American separate-and-maybe-equal system which forced the native population into ostensibly autonomous reservations.* But eventually the barriers between the two species' domains would soften as we learned to understand each other.
Believe it or not, this issue was addressed in the 1970 film
Skulduggery with Burt Reynolds. I haven't seen it since it came out, and I believe it wasn't very good, but I now see it's available on YouTube. Gotta watch it again soon.
I leave with the following exchange from
The Simpsons:
Marge: Lisa, Bart, what did you two learn in Sunday School today?
Lisa: The answers to deep theological questions.
Bart: Yeah, among other things, apes can't get into heaven.
Homer: What? Those cute little monkeys? That's terrible. Who told you that?
Bart: Our teacher.
Homer: I can understand how they wouldn't let in those wild jungle apes, but what about those really smart ones who live among us, who roller-skate and smoke cigars?
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*I suppose I should clearly state that I don't consider Native Americans to be inferior, primitive, a separate species, or deserving of the terrible treatment they received as Europeans settled further and further into the "New World". I am only making an imperfect analogy to the way I think a people we do not fully understand would be treated.