1)
Why is man mentioned last?
1.
Radak: He is the most special in the lower world. Also in creation, he is mentioned last, to teach that he rules over all [other creations].
2)
Why does it mention kings?
1.
Radak: Also the most honored and oldest (verse 12) - all must praise Hashem, honored like disgraced, young like old, men and women.
2.
Malbim: It mentions the rulers, and Le'umim (creeds), officers (a lower level of rulers) and judges (based on protocol and creed).
3)
Why does it say "v'Chol Le'umim"?
1.
Radak: When the redeemer comes to Yisrael, all nations will admit to Hashem.
2.
Malbim: Refer to 148:11:2:2.
