1)
Why does it say "v'Shilachti"?
1.
Malbim: Afterwards there will be a plague and eradication also in Magog's land, and also in islands separated from [most] people.
2)
What is the significance of sending fire against Magog?
1.
Radak #1: He will consume them like fire consumes.
2.
Radak #2: He will literally send fire ? "Esh v'Gafris Amtir Alav" (38:22).
3)
Why does it say "uv'Yoshevei ha'Iyim la'Vetach"?
1.
This is like 'uva'Iyim ha'Yoshevim la'Vetach' or 'uv'Yoshevim la'Vetach ba'Iyim' (based on Malbim ? PF).