1)
Why is "Ki Hinei Oyvecha" repeated?
1.
Radak: It is to strengthen the matter.
2)
Why does it mention "Oyvecha" and "Po'alei Aven"?
1.
Malbim: There are two reasons why they will perish. (a) They are Oyvei Hashem - He will destroy them via Hashgachah. (b) By themselves, evildoers separate; their evil deeds obligate them to separate, and block connection and continuity, and they perish in their evil.