1)
Why does it say "Himsiv"? This is plural - it should say Himsiyu, like "Natayu Raglai" (Tehilim 73:2)!
1.
Radak, Malbim: We find like this in Arame'ic, e.g. "Ishtiv Chamra" (Daniel 5:4).
2.
Radak, citing his brother: It is singular - each of my brothers (the other spies) melted the nation's heart.
