Can my fighter use his Inventor or Medic skill and still collect income or go to the trading post with my leader?
After scouring the ORB the answer is: Yes, you may use inventor and/or medic and then collect income from a territory (if the fighter is a ganger) or accompany the leader to the trading post. These skills do not limit your post game sequence activities in their descriptions on ORB page 91. The only limiting factor is that a fighter that was taken out-of-action cannot collect income or go to the trading post. ORB page 92 states that fighter that went out-of-action if a game cannot collect income.