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.
Always try to keep the Torvald occupied. Your Totemic Ward counters Nullify and his Ultimate, and chances are, the Torvald will cast his ultimate as you and your allies are in range of your Totem.
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.