So say we want to push ~20mA through the LEDs(2V drop), .7V from the emitter follower, and say .5V from beating up the IO lines. 5V - 3.2V = 1.8V, say we want a 100 Ohm resistor. Since this is > .7V, I'd just say connect the resistor between GPx and the emitter follower's output. When the PIC tries to drive the pin high, it'll supply .7/100 = 7mA, with the remainder of the column current going through the NPN, and when the pin goes low, the NPN turns off and we end up with a 100 Ohm current limiting resistor.