concerning the difference of symbol and schematic pins: schematics use components (ipin.sym, opin.sym, iopin.sym) for that, and these components in turn contain a litte red square that represent the connecting hot spot of the pin. Symbols instantiate directly the small red squares. So schematics have one more indirection level. This allows you to create any fancy shape of pins in schematics. In the beginning symbol files were not allowed to place components, so that was the reason for the distinction.