Well, let's think the possibilities through...
1. short gnd and power - should just trip the USB port on the PC, teensy and keyboard would just see a dip in power
2. short ground to signal pin - no problem
3. short power to signal pin - possibly a problem if the teensy or keyboard is sending data, for the sender
4. short ground to LED pin that was 'on' - probably dead teensy, but not sure why the signal pins seem to have died too
5. short power to LED pin that was 'off' - same
Even if the keyboard is damaged, it would most likely just be a cheap buffer chip :-)
(signal = data/clock, LED = caps/num/scrl)