Washoe, her adopted son Loulis, Dar and two companion females, Moja and Tatu. In describing Tatu's character, for instance, he first explains the chimpanzee's fondness for all things black. On one birthday Fouts gives Tatu a present of a black blanket and a black lipstick. I'm not sure what we should be called in this context. Again, this strikes me as overselling the point.
Chimpanzees are, indeed, a bare genetic half-step away from humans.
They are also remarkable beings in their own right. When Fouts isn't caught up in the self-righteousness of his politics, when he's just describing them, he makes that beautifully clear.