Audio problem: Just before the crashed jet skids to a stop, you can hear the jet engines despite them being ripped off with the tail fin quite a way back, so you shouldn't be able to hear them.
Audio problem: After the two treasury agents restrain FBI Agent Mathison, Agent Travers draws his weapon and we hear the sound of him cocking the hammer, however, his thumb stays on the grips.
Audio problem: When Gabe is yelling at Qualen to drop Jesse off on the mountain at the end, he yells "over there" and points to his right. however, he points to the right with the hand holding the walkie talkies as he is yelling over there without any trail off of his voice. his voice can be heard loud and clear as if he was talking straight into the walkie talkie.
Answer: There are two stunt doubles for Mr Stallone on imdb.com, their names are Mark De Alessandro and Jeff O' Haco. The site doesn't specify who did what.
The-Immortal