Why are the current directions in the hybrid-\$\pi\$ model for BJT the same for both NPN and PNP?
It's a small signal AC model, so the DC currents don't matter. Since \$ \frac{dI_{C}}{dV_{BE}}\$ is the same polarity for both, we can use the same model (i.e. a larger b-e voltage results in a larger load current, just they are both negative for the PNP version (which equates to the same result as the NPN)