I think you are considering increasing the complexity of the fuel system four-fold.
The relay is unnecessary, as is the separator. The inertia switch is a bit controversial, I ran an electric pump in the P15 for a year without the switch, and still have second thoughts about it after I installed it....just something else to fail. Not sure an engine fire is our biggest risk in a car that has no passenger crash protection........
All you need to make your car run nicely is a mechanical fuel pump block-off plate, an electric pump, some wire and a fuse. The other items are wants. ?