Yes, we are homo sapiens, sapience is fundamentally a human question. This is why we even care about it in the first place: it boils down to "are some animals human too?" That's why we care about it so much.
Yes, in the past. It's perfectly relevant. The definition redirects to wisdom and sagacity. I'm going to quote from the wiki entry[] on wisdom to demonstrate why the definition is precisely apt.
> Wisdom, sapience, or sagacity is the ability to contemplate and act productively using knowledge, experience, understanding, common sense, and insight.
These are generally the traits we find correlated to animals that we consider to be sapient, self-aware and capable of metacognition, e.g. elephants, chimps, crows, parrots, etc.
Hilariously, this is the result I get from Merriam-Webster: https://www.merriam-webster.com/dictionary/sapience did you even look?