1. Got to go with the Wolves on this one. They have viciousness and skill in combat to match the WE but they fight more cleverly than the WE do.
2. I don't know about this one but I'd go with Angron. They'll probably fight for a while and be a match for each other, Russ will start laughing again because he realises it's pointless and Angron, unlike the Lion who merely sucker punched him, will REALLY take acception to being laughed at and sucker chainaxe him.
The human appendix. Proof of a higher power. A divine kill switch so to speak.
No one really likes a smartass, but people tend to like a dumbass even less.