For easier filling without back splash, I would cut and shut the tank filling vent (#2), then refit the elbow higher, into the bell and extend the tube to reach the existing hose. Then the end of the pump nozzle should extend past/ below the tank filling air vent but below the unleaded restrictor plate (if equipped).
The small tank vent should stay separate from the tank filling vent or a float/check valve added. Fuel rail return to the filler neck instead of the tank is common on efi retrofit, preferably with a bend inside pointing down to the tank for less aeration.
A 5/16 bolt long enough to have a 1/2 inch long unthreaded shank would work well (cut threads off with a hack saw) to replace the screw plugging the return hose or use a rod (bare or zinc plated steel) from the hardware store, cut to length, and radius the end to prevent cutting the inside of the hose. Most rubber barb caps are made for vacuum systems and will fail quickly is exposed to fuel, so use a short piece of fuel hose. If you reuse the existing hose, make sure it is still soft and flexible.