1)
Why does it mention Meshech and Tuval?
1.
Malbim: The verse explains the Arelim that will fight Egypt, Ashur and Eilam. It is Meshech, Tuval and their multitudes, i.e. the army of "Gog Nesi Rosh Meshech v'Tuval" (38:3).
2)
What are "Mechulelei Cherev"?
1.
Rashi: This is like Harugei [Cherev, people killed via the sword].
