What is the significance of "va'Ta'al Echad mi'Gureha"?
Rashi: This refers to Bnei Yoshiyah - the first was Yeho'achaz.
Radak, Malbim: She raised one of her cubs, i.e. one of the princes - Yeho'achaz, "va'Yikach Am ha'Aretz Es Yeho'achaz ben Yoshiyah va'Yimshechu Oso va'Yamlichu Oso Tachas Aviv" (Melachim II, 23:30). She raised him until he grew in stature.
Why does it say "Kefir Hayah"?
Radak: He was called a Kefir, but not an Ari, for he did not have a great kingship; most of the land was destroyed then.
Malbim: He reached his power to be king, and learned to tear, like a Kefir.
Why does it say "[va'Yilmad Litraf Teref] Adam Achal"?
Rashi: He steals Yisrael, who are called Adam - "v'Aten Tzoni Tzon Mar'isi Adam Atem" (34:31).
Rashi (according to the Mashal): Any Chayah that tasted human flesh, it will always confront people.
Radak: This Kefir learned to tear prey, until it ate a person. Most prey of an Ari or Kefir are Chayos; sometimes they tear also man.
Radak (according to the Nimshal): So Yeho'achaz fought those greater than himself, e.g. Egypt, like it says in Sefer Melachim; due to this, Pharaoh Necho incarcerated him.
Malbim: Based on nature, a lion does not eat man. Hashem put fear of man on Chayos. It left his boundary to eat man.
Malbim (according to the Nimshal): Yeho'achaz destroyed also from Yisrael - "va'Ya'as ha'Ra b'Einei Hashem" (Melachim II, 23:32).