Ok, I'm too tiered to read all of this, so I'm sure that it's been said, but to what you're referring to, is to the missing link, but creatures that evolved along side humans, those would be the Nethendrathals and those hobbit like speacies, they both died out, and Hobo sapians were the only ones like us remaining.
As for you missing link, they have been found in Africa, but they too died out, our closes living releatives are the apes, but we didn't evolve from apes, we evolved alonged side them, so technically speacking, apes are our "brothers" or "cousins", not our "fathers" or "uncles" (You can turn this into mothers, sisters and auntes if you want to take a feminist approach, but I said them in their mascline form for the sake of a metaphor), we share a missing link, an ancestor with the apes.
And I'm pretty sure that's been found aswell, just in fossil form.
But the jungles of Africa (Expecially the Congo), and South America (Expecially the Amazon), are huge, and it is almost certain there are speacies there that we have not yet discovered, like in the ocean, so who knows, there was that Okupai girraffe thing that got discovered only a couple of years ago in the Congo, and they found an undiscovered monkey thing, which was huge, and stood upright, altough it hasn't been proven real, as they shot one. But there is a photo of it.