Both the FPR and the injector would leak into the intake, but they would usually be at lower rate. Pull the vacuum hose from the FPR and check for gas, or a gas smell. If it'* there replace it, and don't start the car until you do.
You could pull the fuel rail, pressurize it, and check for any leaking injectors.
If I had to make a one choice, out of the 3 without further testing, I'd go with the most likely cause of the fuel pump. I would strongly suggest at least the FPR check, as that can lead to an explosion in the UIM if it is bad.
Black 2000 SSEi, Silverstar Headlights, Angel Eyes fogs, 3rd brake light overlay, hi-flo cat, drilled 180 degree thermostat, Intense FWI, PCM, shift kit, and 3.4 Pulley. Solid front mount.