The purge valve (Y58/1) is a solenoid valve. When the engine is warmed up and the ECU feels like it, the purge valve pulses open and allows engine vacuum to draw fuel vapors into the intake from the charcoal canister. It is in the engine bay on the left-front shock tower (looking forward). You can feel it pulsing when it is operating. I think the majority of the air drawn in must be coming from the incoming air shown entering the charcoal canister on the drawing.

I think you are right about the vent valve (76) opening to allow fuel vapors to pass through and be trapped in the charcoal canister when refueling. It may be a one way valve because I believe the gas cap opens under slight vacuum and allows air to enter the tank as fuel is consumed.