OK, so I just finished the soldering job of replacing my arduino UNO with a Teensy 3.1. Still reluctant to power it up as I still have one concern. Are momentary buttons still just a short to ground at a specified analog pin?
It should not be a direct short. That will kill your controller pin. There needs to be a resistor. Something like this:
https://www.arduino.cc/en/Tutorial/Pushbutton
Also be aware that the Teensy analog only pins (A10-A14) are not 5V tolerant, but only 3.3V.
Reason for a pull-up resistor is not to avoid a short. Without a resistor the voltage is floating and the pin will read sometimes high or low. The resistor provides a defined level.
There is also the method to use
pinMode(button1, INPUT_PULLUP);
This enables the internal pullup resistor of your µController and you do not have to solder an external resistor.
However, be aware that the logic is then reversed: Button1 pressed == LOW.
Btw. if you use analog pins for a button input you should declare the analog pin as digital pin:
A0 = D14 … A5 = D19 (also works on Arduinos)
DigitalRead is much faster than AnalogRead.
So searching for a resistor on hand, the highest resistance I have is a 1k ohm. Should be OK when using 3.3v right?
Yes, that will work.