That library does not use the touch sensing capability of the Teensy 3. If I read it correctly, it was written to work on a Nano or Uno etc. It measures the capacitance between two pins by grounding one of them (in your case pin 16) and timing how long it takes for the other pin to drop below a threshold value.
You don't need to do this on Teensy 3. The touchRead function works just like the analogRead function except that it reads capacitance instead of voltage.
Try this demo sketch I've just tried out on my T3.
It just prints the value received by touchRead on Teensy3 pin 23 (A9).
When the wire is touched, the sketch prints a number above 2000. When the wire isn't being touched the number is around 800.