1)
Why does it say "va'E'eseh Lema'an Shmi"?
1.
Malbim: It was lest Shem Shamayim be profaned, lest they say "b'Ra'ah Hotzi'am Laharog Osam be'Harim" (Shemos 32:12), and "mi'Bilti Yecholes Hashem Lehavi..." (Bamidbar 14:16)