From your (Jewish) link:
2. Because the scapegoat acted as an atonement for all of Israel, the High Priest confessed upon it in the name of all of Israel. As it’s written: “And he will confess upon it all of the transgressions of the Children of Israel ....” (Leviticus 16:21).The scapegoat would atone for all the sins in the Torah: for the serious ones, and for light ones; for those done purposefully, and for those done accidentally; for those the sinner was aware of, and for those he was not aware of — as long as the sinner did teshuvah. But if he didn’t do teshuvah, the scapegoat would only atone for light sins. As to which are “light” or “serious” sins, the serious ones are those that incur a court-imposed death sentence or spiritual excision. Vain and untrue oaths would also be serious sins, even though they don’t incur excision. All other prohibitions and imperatives that don’t incur spiritual excision are light sins.3. In our days when the Holy Temple no longer stands and there’s no longer an atoning altar all there is, is teshuvah. Teshuvah atones for all sins. Even if one were a wrongdoer his whole life but he did teshuvah in the end, all his wrongdoing would go un-cited. As it’s written: “And the wrongdoing of the wrongdoer will not make him stumble on the day he does teshuvah for his wrongdoing” (Ezekiel 33:12)
So Teshuvah (”return” [to G-d], ie, repentance) was and is still necessary and is in fact the main ingredient to salvation, not belief (faith) alone.
And we see that no non-human has to die.
Your questioning strives to equate your lamb with a goat, doesn’t it?
Plainly said in Leviticus 4:17.