1)
What is the significance of these nations?
1.
Malbim: All of them are Bnei Cham - "u'Vnei Cham Kush u'Egypt u'Fut; ... u'Egypt Yalad Es Ludim" (Bereishis 10:6, 13). All of them will fall to the sword with Egypt.
2)
Who are "Kol ha'Erev"?
1.
Rashi: All who give Arvus for Egypt (its guarantors). This is like Targum Yonasan 'Sumchavasa'.
2.
Radak: A nation comprised from different nations that became mixed. This is like Targum Yonasan 'Sumchavasa', an expression of a mixture.
3)
What is "Eretz ha'Bris"?
1.
Rashi: Those who made a Bris with Egypt to help her. Radak - they were not Egyptians or from their families, but because they had a Bris with them, they were stricken with them.
