1)
Why does it say "Kol ha'Neshamah"?
1.
Radak: All these praises are of the Neshamah. It contemplates Kel's actions. Knowledge is according to the power of the Neshamah while it is in the body. The Neshamos should praise Hashem!
2.
Malbim: (a) In any case, praise of Hashem will spread from above to encompass all creations; every Neshamah will praise Him. (b) For every Neshimah (breath), one draws Ru'ach Chayim and Chesed, they should praise Hashem for His Chesed, benefits, deeds and wonders, for his mercy and Chesed never cease.
