You can use analog pins A0..A9 and A15-A20 (on pads underneath the Teensy 3.2) as digital pins using pinMode on the Teensy 3.2. You cannot use pins A10-A14 as digitial pins (A10-A11 are on the inside row of pins, A12-A13 are on the underneath pads, and A14 is on the back row). Basically if you look at the pinout card, and it has a digital pin number in gray, it can be used in a digital context. On the Teensy 3.1/3.2, the digital pins are 5v tolerant, but the analog only pins are not 5v tolerant.
On the LC, A10-A12 can be used as digital pins (the LC does not have pads underneath for more pins, and the pin that is A14 in the Teensy 3.1/3.2 is A12 in the LC). On the LC, no pin is 5v tolerant. There is a special pin (A3 or 17) that is level shifted to 5v for an output pin, but you can't attach a 5v source to it.
If you still have the original Teensy 3.0, it did not have analog inputs A14-A20 (those pads were just digital inputs), and the 3.0 was not 5v tolerant.