If you want to test if your Phidgets are working on the Raspberry Pi, I would recommend setting up python
for Linux and running the python example for your device (go to the product page for your device and see the "code samples" tab.
If the thermocouple is connected and working, this example will print the thermocouple temperature to the screen until you press a key. If you don't have a screen and keyboard attached to the Pi, you'll have to remote in using SSH to run the example.
As for the drivers, it's ok to have both Phidget21 and Phidget22 installed at the same time.