DOCTRINE
Avoid Vexing Bolt and keep track of Spectral Assistant, which adds attacks and gives Sinclair a position to swap to. Avoid Rabbit Hex before it prevents you from acting; it does not interrupt abilities already running. Land Threadsap from cover and follow with gunfire while you hold stolen Spirit.
Pressure Sinclair when Rabbit Hex is unavailable, while watching the Spectral Assistant he can swap to. Use your ultimate when it helps the fight; withholding it does not prevent Audience Participation from choosing it.
Start Feed The Birds after Rabbit Hex is spent, with teammates close enough to stop Sinclair reaching you. Respond to a copied ultimate when he casts it, and leave your channel if that attack makes your position unsafe.