Try to wait until after Terminus uses his ult to use yours on him. If you Dragon Punch before he ults, he'll just come back to life and you'll be at risk of being in the blast.
Be very careful of Khan ult, as if Inara gets thrown off the map, she has no way to save herself. You can use the Mother's Grace talent to give him fewer chances to attempt to grab you, otherwise play carefully with lines of sight.
Sha Lin's ultimate can make him hard to track, but throwing down a Sensor Drone near where he was last seen will reveal him for your team and partially negate his ult.
Strix's stealth can make him harder to track, so toss your Sensor Drones out where you expect him to be and reveal him to your team. If you run the Booby Trap talent, the explosion of your drones can disrupt his aim or throw him off of high ground.