1)
Why does it say "mi'Mizrach Shemesh Ad Mevo'o Mehulal Shem Hashem"?
1.
Radak: All people are between east and west; all should praise Him. Even though idolaters are among them, all admit that He is the First cause - "mi'Mizrach Shemesh v'Ad Mevo'o Gadol Shmi va'Goyim" (Mal'achi 1:11). It mentions east and west, for most settled areas are [near] the equator.
2.
Malbim: Praise spread [everywhere,] also among idolaters, but they do not bless Him.